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Acid testing for gold, silver & precious metals

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Topic 36471 "How to Test Silver at Home"

Q. I found a nugget it looks exactly like gold when I tested on my kit it comes out gold all the way up to 22 karat I took it to a dealer he tested it it came out positive on his test kit he said he would send it out to get tested and he said it came back that it wasn't gold. How is that possible?

Michele Kitredge
- Glendale Arizona
September 23, 2023

Q. Dear Sir/Madam:

I would be grateful if anyone can supply any information about how to understand the different karat of gold? Is there any solutions to purchase or to prepare which would tell me the exact karat of the gold jewelry?

Thanks in advance.

Fatma A [last name deleted for privacy by Editor]
- Istanbul/Turkey

Ed. note: Read on, Fatma -- that's what this whole long thread will be about. Quick acid tests can give some indication of karat, but 'exact karat' is unlikely.

"Gold, Platinum, Palladium, Silver & Other Jewelry Metals: How to Test, Select & Care for Them"
by Renee Newman

on AbeBooks,

or or eBay or


(affil links)

Q. I am an amateur (hobbyist) buyer & seller of second hand & antique jewelry and need to verify composition in order to honestly describe what I sell. Recently bought a testing kit [on eBay or Amazon] on eBay. The silver testing bottle is dark amber in color. As a trial run, I scratched the stone with various silver-colored metals--anything from steel to marked sterling to "mystery" metal. I observe no reaction whatever with any of them. Does the reaction occur instantly? Can I use another type of stone instead of the dark gray one that came with the kit? Or could the liquid in the bottle be defective? Instructions with kit were very sparse. Would appreciate any suggestions.

Jane Bagg
hobbyist - Punta Gorda, Florida

A. I've never used a jewelry test kit, but I am a chemical engineer, so I'll make an educated guess at your problem. My first guess is that the liquid in the bottle is some sort of acid, either nitric acid or a 75% nitric acid/25% hydrochloric acid mix also known as aqua regia. I know you will get a reaction from either silver or gold if they come in contact with either acid, although off the top of my head I don't recall what color you'd get. But there would definitely be a change, or else the metal would completely dissolve. You should see a reaction right away, in under 30 seconds. And yes, it's possible that the acids could go bad over time (say a year or longer) or if the bottle wasn't sealed.

My second guess is that the purpose of the stone is to scrape off enough metal to get a reaction to the acid without doing too much damage to the object you're testing. So the stone just needs to be sharp and resistant to acid. Is it possible that you didn't scrape off enough of a sample on the stone to get a reaction?

If you have an item that you know is silver and don't mind it getting damaged, you could take a drop from the bottle and apply it directly to the silver and see if you get a reaction. No reaction means the liquid is bad, any reaction means you didn't get enough sample on the stone. Or you can write off your eBay purchase and buy a new test kit with instructions; try typing "silver test kit" into Google. If you have access to a local junior high or high school with a chemistry lab you might be able to sweet talk a teacher into testing your liquid or some of your objects, especially if it could be worked into a classroom lab practical and/or demonstration.

Hope that helped. Good luck with your hobby.

Linda Corrie
- Orland Park, Illinois

A. Hi,
I bought a similar test kit [on eBay or Amazon] off of eBay from a guy who sells many such kits. It included 3 bottles for different purities of gold and one bottle of solution for testing silver. I believe the gold solutions would be the aqua regia and the silver solution is most likely just nitric. Anyway, when I first used the solution it worked very well. Anything made of sterling or purer would immediately turn the solution a blood red color and the silver (if I had put a piece in directly)would turn very dull. The solution also bubbles as it is reaction with the metal. I often would get bubbles with other metals, but the solution would turn blue (copper indicator I believe) or yellow. I have now had this same bottle for well over a year and it does not appear to be working any longer. In fact, that is why I was on the internet searching "Does silver testing acid go bad?" I am guessing from your experience and mine, and the other persons comments that the solution does, in fact, go bad over time. :(

Guess I need to buy a new bottle myself. The first one did work a good long time, though.

Lisa Ferreira
- boulder, Colorado

A. As far as I can tell that means it's rhodium plated, but I suggest buying a test for that too. As a fellow hobbyist, I get confused by the kit you have too. Best of luck!

Laura Grigsby
Hobbyist - Hillsboro, Oregon
February 13, 2022

Q. Hi,
I recently purchased the silver test kit [on eBay or Amazon]. It seemed to work well as I always had an instant reaction after applying it "to a piece of silver". The instructions say that bright red reaction is "true silver" and dark red or cream color is "Sterling" / or greyish-brown "77%-90% and light green color is 65%-75%. I have a dilemma, I was hoping someone could help me out with. I put a drop of the solution on this gravy boat that I bought at a thrift store. The first reaction was bright red, then it went to a dark red and stayed dark red (forever). I was confused so I went to a pawn shop and asked them to test the piece. They told me that the only way to be sure is to actually cut the piece because the silver plating might be really thick. So I cut the clawfoot of the piece and got a lot of bright silver shavings. I cut it pretty deep, then applied the solution and it turned greyish-black? I did this several times with the same reaction. Can anyone tell me what I have here? pure silver? sterling? Nothing? lol I would greatly appreciate it. Thanks so much.

Lori Wilkins
- Sioux Falls, South Dakota
April 3, 2008

A. I have done a bit of testing on various silver colored objects I have. With my NEW bottle of silver test solution (My previous problem was that my solution had gone bad, I would get a reaction just as you describe with any item that was silver plated. I tried this on some old silverware that was marked as silver plate and got the same reaction. My best guess is that what you have is fairly heavily plated with pure silver, hence the initial reaction of the bright red. My guess as to why it stays dark red even after a long time, is that the plating is heavy enough that the solution is used up before it eats through the heavy plating. Your test after the deep cutting shows that the metal underneath is not greater than 75% silver, though my guess would be it is not silver at all. You are getting some reaction as there is still some of the silver plate touched by the test solution. You could try putting more solution on the first area you did to see if you can get thru the plating. It may take a couple of tries depending on the thickness of the plating. I believe your deep cut test already gives you your answer that it is a silver plated item, and reapply solution to the previously tested (but not scratched) area will merely confirm those results.

Lisa Ferreira
- Boulder, Colorado

A. Lori Wilkins: I suggest testing a different area on the gravy boat. It has been my experience that the feet on boats, platters and the like are not Sterling but a plated composition. The reason being is sterling silver is very soft and will bend easily, compromising the stability of the item it is supporting. The last thing you would want is the feet of a coffee pot, for example, failing and spilling hot drink all over the table. It would only make sense that the feet would be made from a non-bendable material. I never test the feet on an item until I am satisfied the item is in fact Sterling.
I have used the silver acid in the past but did not have the best luck with it. I found the results difficult to decipher. What I use instead is 18k gold testing acid on the scratch test. This will turn the strike mark a blue white color, almost as if the strike is glowing. If I am applying the acid directly to the item in question I will use the 14k gold acid. First I scratch a deep line in the item, do this on the bottom or inconspicuous area if item is not being scrapped, making sure to go deep in case there is a heavy plate on it. I then apply a drop of 14k acid to the line making sure to get acid not just on the line but also on the silver around it. If it is sterling the acid around the line will turn a creamy white opaque color and the line will turn white or at least lighter than the opaque around it. If the line turns green it is not Sterling. Pay close attention though because 800 silver will not show as sterling completely nor will it show as plate. The results will be a combination of both results. They will be inconclusive. That is a good indication the item is 800 silver. 800 silver is almost as valuable as sterling.
Now if when testing for silver with the 14k acid on an item and the acid rises up slightly and looks like salt or calcium scale your item is pewter.
I hope I have been able to enlighten you with this answer.
Happy testing.

Gothica Fisher
- Wittmann, Arizona
May 23, 2022

Q. This is interesting, glad I checked, not sure I want to buy a testing kit now. I have been buying & selling silver-plate & sterling for years, just started to step it up a bit and advertise for scrap sterling. Sometimes I run into Mexican Sterling, not sure a test kit would help. I guess I will shy away from it unless it is marked with some kind of verifiable mark. I was surprised that the test kit would react to silver-plate (which is silver) the same way as sterling. Silver Electroplate is silver but so thin you could rub it off with light sandpaper. Then there is Sheffield Plate which is Sterling with Copper sandwiched in the middle for weight & durability. Then there is Nickel/German Silver, which is a mix of Sterling and other metals. A test kit would be useful for that. Most US & European sterling is clearly marked. I think I will rely on that.

Richard Rogers
- Kona Hawaii
July 22, 2009

A. A small correction. "German silver" does not contain any silver at all.

Herbert Fellows
- new york, new york
January 12, 2011

Q. I have some Mexican silver and it shows the test as brownish yellow and the test sheet shows that the test is 90 to 100% silver; am I correct?

ray robey
hobby - temecula California
March 1, 2010

A. The test colors for silver that you have posted appear to show silver content at 80% silver but the yellow reaction indicates a base of tin which would be common in Mexican silver.

Kerry McGee
- Prescott Arizona USA

Q. Ok ... so I know something about testing for silver ... But what does the color yellow mean? No silver? Bad solution?

Laura Andersen
August 30, 2010

Ed. note: In the post immediately before yours, Kerry G says it means tin.

Q. I am totally new to silver and color blind LOL!! I am only interested in purchasing .999 rounds and bars for investment sake. What are my best choices for testing in this situation? Is acid the only way to determine quality? Would appreciate any help!

Ron Cox
- Mesquite Texas USA
March 25, 2011

Silver Test Kits

on eBay or


(affil links)

A. If at odds for testing silver with acid, try using any gold acid on the silver; it'll turn milk white and stay milk white. If silver is plated the gold acid (10 kt--up) will eat through the silver plate and start eating the base metal, by bubbling and acid will turn green. it's a foolproof method, and you clean the acid spot with jewelry rouge [on eBay or Amazon].

roy weatherford
- marietta Georgia usa

A. You can test silver with acids used for gold, but you still need to get past the silver if it is plated. (Plated will show that milky white also) I use 18K acid and test twice making sure I use heavy pressure when marking the stone.

Robin H Murphy
- Palm Beach Gardens, Florida

A. There are several ways to find out if an item is silver or gold. The first destroys the item but if it's scrap what the heck. It is called a fire assay. The second is a specific gravity test and takes a triple-beam scale. You may do a google search to get full instructions. We have sold test acid for years and yes some of it goes bad with time. If you have a silver scrap item, apply it direct to the item and it should turn blood red if it is 90% silver or more. The less silver content, it will either turn yellow, dark brown or if it is plated it will turn green.
They make acid that will test 10k-14k-18-k 22k and so on. I believe the 10k acid is nitric. I always file a notch in the item and apply direct when you are buying gold that goes for $1500 an ounce. You may use a stone but test needles will help as they have nearly any karat you might want to check. When buying silver or gold on eBay , make sure that they don't use a postal scale as they are not accurate. Hope this will help. This is our 50th year in the rare coin biz! Regards!

B. M. Burk

A. The first mistake is that when you test silver you DO NOT MAKE A SCRATCH on stone like you do with gold.
You need to make a small cut with a file preferably 3-square on your silver piece and put a drop of acid on this fresh cut. If this is silver there will be no reaction, but if not you should immediately see formation of green bubbles.

Aqua regia is a mixture of 75% Nitric and 25% Hydrochloric (Muriatic) acid, as correctly pointed by Chemical Engineer. However it is used for refining gold not for testing it.

Mark Landa
- New York, New York

A. Ron you mention you are color blind and so acid color testing would be difficult.

I suggest they manufacture a very nice test unit that checks the round/coin It is a heavy duty plastic slab with a balance projection underneath. If the coin passes muster with weight, thickness, diameter and balance, then it is the real thing. One advantage is you can carry it in your pocket. A different fisch is needed for each type of coin.

I have no connection with thefisch company, but I do own a set.

Brian Fahey
- Hunt New York, USA
June 20, 2016

Q. If you have made a cut into the piece, why would you need the acid test? Wouldn't the cut alone visually tell you if the interior was copper or brass or??

Or is there a metal I'm unaware of that naturally appears to be silver that isn't that could be used as a core on silver plate?

Herb Fellows
- New York, New York
June 3, 2011

A. Hi, Herb.

Most silver plated flatware is nickel-silver under the silver plating, rather than copper or brass. Nickel-silver contains nickel but it does not contain any silver.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

A. This is how I was finally able to see results with the silver tester acid from eBay . I also bought a bottle and could not see ANY change in color when put on the stone after a rubbed the item on it. Rub the item on the stone.Then put the drop of acid on it. You will not see any change in color. But then wipe (dab)it off the stone with a WHITE piece of flat paper towel or napkin. With non silver the part of the napkin will turn blue/brown but then to clear. With silver the napkin spot will still also turn clear but there will be little red specks in the spot. Those I believe are the silver traces. This works and I have tested many different metals to be sure. Try it side by side on the napkin. One piece silver and the other non silver. You will see the difference and now know what to look for. The sellers tell you to look for a color change that never happens.They should give better instructions.

Frank Smith
- Seaford, New York

Q. My question is two part, but simple. I have a sizable amount of something I believe is gold. If when I went to have it tested they used aqua regina instead of nitric acid to test would that make the metal seem like it is not gold? Secondly , How would a person tell if that happened?

My insight leaves me wondering why use an acid that is known for breakdown of gold to test gold? Nitric acid is to show karat difference. I'm thinking when I had a test of this sort done, instead of nitric, someone used aqua regia. Do you know the answer?

margaret neanover
hobbyist - hamilton Ohio
June 13, 2011

Jewelers Rare Earth Magnet

on eBay

or Amazon

(affil links)

Q. I recently purchased by mail order a $79.00 Gold, Silver, and Platinum testing kit with the acids...the supposed "stone" was a piece of glass that I received chipped, the Platinum Acid had been opened, and the 14K Gold testing Acid smokes whenever I open the little bottle.

Jewelry that is marked 18k gold and was previously tested as 18k-20k by Smyth Jewelers, is being dissolved on the stone by the 14k acid. Do I have a BAD kit or am I doing something wrong. They REFUSED to make good on their product or give a replacement or refund, all they say is, "...We have never ever heard of a bottle of our acid 'smoking' ", and are treating me like I am lying or weird.

I also have a 5 1/2 inch by 1/2 inch bar of something white metal colored when I put Silver acid solution directly on it nothing happens, when I scratch it on the stone and add the 14k solution it DOES NOT dissolve, can Nickel or Steel give this kind of positive or do I have Silver or Gold, oh yeah and it does not react to a rare earth magnet.

CoCo Sainte-Laurent
- Baltimore, Maryland
June 21, 2011

A. eBay has a satisfaction guarantee, and you are not satisfied.
If you still kept the purchasing information, include it at the end of your letter. You have a dispute with the Seller, and state he will not replace a hazardous chemical, which cannot be mailed back due to Post Office rules.
eBay is terrific and you WILL get your money returned.
I hope this helps.

- LAKEWOOD, New Jersey

A. Hi CoCo,
I agree with Barbara that you should get your money back from wherever you bought it. Asking people on the internet to try to figure out for you whether, it addition to broken components, and in addition to opened bottles, yet another bottle in the kit is defective or not based on reaction with an unknown metal is just a waste of time.
Luck & Regards,

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

Q. Hi, I have a question about how long to leave the acid on. Is this an immediate change? I just tested my first medal - I bought it as 'test silver, no mark' . When I received it in the mail, the front indeed 'looks' like silver, but the back was just a bit too shiny and chrome-ish, so I tested the back. It was dark red, then over the course of a few seconds went to dark brown, and then started getting a creamy greenish, which I realized was the medal actually being eaten! I wiped it off and yes there is a big dull spot about 5 mm wide, but under it is a pretty creamy silver color. :) But it's a little sparkly and I know that means nothing, basically. But I'm wondering, should this have been a one-second reading? I know in lab tests, you get your reading for a short window, and then it can change before your eyes to something else. Any ideas?

Megan Crisp
- Asheville, North Carolina
July 21, 2011

A. So easy...when I test for silver with my silver acid, if it's real silver, it turns bloody colored - any other color, it is not silver. Within two minutes of testing you'll have it down. I've never been wrong yet - I either scrape on the stone or easy.

Lisa rendon
- reno, Nevada

Q. I just bought a bottle of Griffith silver testing solution from our local jeweler that he had ordered it for me, so I know it is fresh.
I rubbed one of my wife's rings on my gold testing stone and then pulled a drop of the testing solution across the rub. the testing solution made the rub go disappear. The ring was marked "sterling". What did I do wrong, or is that the way it is suppose to work?

Ed Ercanbrack
hobbyist - Sinton Texas
August 9, 2011

A. Ed,
I am confused as you are also.
I test silver all the time.
Same way as you and never had
"No reaction".
I think the product is bad.
I know mine over time tends to be unreliable. So shelf life depends on how long it's already sat at buyers, and how long after purchases.
On important or mixed answers I'll use two bottles of testing fluid and then compare my answers.
Good luck with your mystery?
Hope you didn't buy water?

Rita Shaw
Hobbyist - Warwick Rhode Island
April 7, 2022

Q. I got ripped off at an antique store or did I? I went to test my silver purchase out at a "we buy gold" place. the guy first tested it and it was silver he said. Then he told me to go home and cut it in half so he could see if it was solid I came back and he tested it again he said nope not silver what? After ruining the piece he didn't want it. I'm confused he tested it with an acid. It made the silver black -- what does that mean?

Anthony Salas
hobbyist - glendale, California
August 17, 2011

A. Hi, Anthony. If the antique store claimed that it was Sterling, I think they owe you!

But assuming you did not pay the gold-buying shop to do an appraisal of your find, I wouldn't be hard on them; you misunderstood each other. If you didn't pay them anything for their time & effort in evaluating your find, the assumption is that the reason they were doing this for free is that you would like them to make an offer to buy the silver for its intrinsic (melted) value. They tested the surface without devaluing the item and told you there was silver on the surface but they were unable to tell you if it was just plating (worthless) or solid silver from that. You asked them if they were interested in buying it and they said they couldn't answer without cutting the item in half. They apparently feel that it isn't silver so it has no scrap value. Sorry for the disappointment :-(


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

A. As stated earlier, you can use a scratch stone when testing silver/sterling silver with a test acid. Scrape your piece on the stone in several spots. This will help get you past any plating that may be there. Check out the color of your scratches on the stone. They should all be silver in color. If you get any other colors, such as tan, it is not silver. Now add a drop or two of your acid and wait about 30 sec. Don't wipe the stone because this will remove any of the material and the acid and will leave the stone clean. Instead, rinse the stone off under the faucet and check the color of your scratch. It will be red if the piece is silver. This technique has worked well for me for over 20 years. I do replace my acid at least once a year.

Brian Christoff
- Jacksonville, Florida

A. Anthony Salas: If the metal turned black when acid was applied it is very possible the item is 800 silver which is almost as valuable as sterling. I have acquired items in the past that were marked 925 or sterling only to find out it is 800 silver instead.
Next time you take your silver in question to be tested first ask yourself what you intend to do with the item if it is not Sterling. If you plan to keep the item or try to sell it or return it then you will want to test it without damaging the item. Also ask yourself if it is sterling what are your plans for it. If you plan on keeping it or selling it you would want to use the least invasive yet accurate test available. Using a strike plate is your best choice -- just make sure to use an inconspicuous area to scratch. The same if you have to scratch the item itself. Keep in mind the acid can be removed from the item, the same as any green that may appear if the item is plated, but the acid will remove the plate and expose copper or brass if present so the smaller the test area the better.
I've heard horror stories about people taking items to be tested only to find out the item is plated but the tester destroyed the item in the process without giving any consideration as to what you had intended to do with said item. So it is very important to inform the tester of your intentions prior to handing the item over to be tested. Never rely on the tester asking because he may forget and you may become distracted and forget to tell him. The more control you have of the situation and the more knowledge you have of your item the less likely mistakes will be made and the less likely you will be taken advantage of.
Hope this helps.

Gothica Fisher
buyer and seller of all things metal - Wittmann, Arizona
May 23, 2022

Q. I've been using the same bottle of silver testing material (nitric/muriatic acids) for about two months with success. But now, all of a sudden, everything tested tests positive for sterling ... even stainless steal flatware. I have cleaned the scratch plate with soap and water, but still get the same results. Anyone have an idea how/why this is occurring?

Patrick Moore
eBay seller - Long Beach California
August 30, 2011

Q. Where can I purchase silver testing solutions [on eBay or Amazon]

Evelyn Hilliard
- Middletown, Connecticut
December 21, 2011

A. Most "gold test" chemicals are in fact various strengths of "Aqua Regia",(the strength depends on the karat value), The primary purpose of the testing stone is that it removes a thin layer of gold to its surface, the aqua regia solution will completely dissolve the scratch if the item is in fact lower than the karat value of the test. Someone stated here that the test was %75 Hydrochloric(muriatic) and %25 nitric acids.....This is in fact (at these percentages) a solution called Aqua Regia which would dissolve even 24k pure gold, therefore would not in any way be suitable as a testing mixture.
I have seen many comments about using nitric or pre mixed gold test solution for testing silver, This is in fact correct. When testing silver with a gold test solution or nitric, sterling or pure silver will turn the piece milky white as stated, , and any gold test chemical above 14k will generally break the barrier between the silver plate and any base metal.
While testing gold on the stone is preferable, silver should generally be tested directly on the piece, if using 10 or 14k test solution you should leave the drop on the piece for at least a full minute so that the solution can have a chance to break through any plating to the base metal. After testing, the white spot can be buffed out again leaving your piece in its original condition....if the piece is silver plate, you may (or likely will) end up with a permanent spot where the plating has been removed.

Ed Meyer
- Kansas City, Missouri

A. I put a drop of the silver test acid directly onto a Rogers "deluxe plate" spoon, and another drop directly onto a silver US dime. I knew the deluxe plate was pretty thick, because I had rubbed it real good on a stone and that had still tested sterling, and there was no visible copper alloy on the rubbed area of the spoon (I already knew the base was a copper alloy from other damage to the silverware). Anyway, applying the acid directly onto each item, both turned blood red, then the liquid turned pretty much colorless, and there was what looked like a dark gray stain on the metal under the liquid in both cases, with just traces of red. Then I rinsed. The plated piece was deeply etched, but not the dime. I had to turn the dime at an angle to see where it was slightly dulled. The difference was subtle, and almost certain to be overlooked at a casual glance. I then applied a second drop to the silver plate, rinsed, then applied a third drop. The third drop turned blue-green. I imagine there are some pieces out there even more heavily plated than this one, but this might be a helpful testing technique to discover heavy silverplate if all you have is the silver acid test.


A. You guys are doing this all wrong! Why would you damage your silver bar or coin etc..?
What you need to do, and is much more accurate as well as non-damaging to your silver, is a water displacement test. I am a Chemistry Major, I can tell you that this is "Chemistry 101". It's very easy to do!

- weigh the silver piece on a digital scale [on eBay or Amazon]
- fill a beaker with water
- read and record the water level (in milliliters)
- put silver bar, coin, irregular shaped, etc.. in beaker
- read and record the water level again
- record the difference in water levels.

This information will allow you to determine the density of the object. The density for silver should be precisely 10.49 gm's per ml.

This seems a bit more cumbersome, but most likely the very best test. Kind of like a DNA test for metals.

Formula below:
Density (should be 10.49) = weight (grams) / ml of water displacement

Chuck Molar
- Concord, California

thumbs up sign Thanks, Chuck. Good idea! But I'd call that a quick "disqualifier" test to show that something is not silver, rather than a "DNA test". Because it's pretty easy to mix together a metal that is heavier than silver with another metal that is lighter than silver, maybe leaded pewter for example, in a proportion so as to get 10.49 g/cc.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

Q. I have a set of silver flatware that was custom made in India. It is stamped Silver, and is probably more than 50 years old. I would hate to damage it but I would like to verify if it is sterling.


Daniel Erickson
Hobbyist - Los Angeles, California
February 22, 2012

A. The Alternative way to test for silver with the Acid sold on eBay is to first of all get a clear full glass of water ready, get your Acid ready and an object like a file suitable to file a metal surface that can be used to file a small area of what is suspected to be silver metal.

File this very well and deeply to accurately test for silver instead of getting confused with silver vs silver plated.

When you are done filing very well put a drop or very little drop of the Acid over the area that was filed.

You should notice a reaction in that area, that acid kind of turns milk color and the silver changes to kind of gray then immerse that section/area into the glass cup of water then a further reaction with the water should show what looks white like a smoke going down the cup, kind of cloudy.

Adesugar Tenkejojo
- Lemon Grove California

"Scrap Sorter /
Alloy Sorter"

from eBay or

(affil links)

A. Hi Daniel. If you have a friend who works in a scrapyard, he may well have an alloy sorter hand-held X-ray fluorescence tester [on eBay or Amazon]. These are very expensive, around 40K, but are non-destructive and so handy that many if not most scrapyards have them.

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha - Pine Beach, New Jersey

Q. Treating lower karat silver does work with acid; it always turns green even when it is silver. So if use "silver acid" what color will low karat turn? There's a lot of people mistaking low karat for plated. Can anyone clarify?

Crris Ali
- Bridgeport Connecticut
August 1, 2012

Q. How to make a silver liquid from silver powder? I just want to know it sir. Please answer my question.

Kyaw Nandar
- Myanmar, Yangon
November 5, 2012

Q. Wondering if there is a way easy enough for a non-professional to test a sample of material claimed to be made of Rhodium plated sterling silver - if it is indeed as claimed?

Jeff Ezers
- Larkspur, Colorado, USA
December 6, 2012

Q. Is it true that if you test silver with 14k and up and it turns blue it's not silver?

Joseph Cancino
- Norwalk, California
February 9, 2013

A. Hello,
If you test with 18k acid a sterling silver piece will turn a milky blue color immediately. Ive researched this and tried it and it does work. So try the 18k acid to test silver. If you test something you know is silver first you will see the color the sterling turns.

CSV Carol Viltro
- Wintersville ohio
February 16, 2023

Q. I have some "gold" coins I own, and a testing kit. I dropped 10k test on the coin and no reaction. Filed a grove in it and did the 10k test directly and no reaction. The 14k test dropped directly on it turns aqua blue and bubbles. From my research the 14k test tells me there is no gold, but the 10k test is telling me it is gold. Help anyone?

David Herron
- Hattiesburg, Mississippi, USA
March 21, 2013

Q. Some years ago I purchased some jewelry for my family from a Jeweller I knew personally in our small Town, whose family has run a business for over 50 yrs.
One item I purchased was a heavy curb link sterling bracelet marked "ITALY 925". This item has been tucked away for years and never worn until recently!
After wearing it for approx. 3 weeks, yesterday I noticed a difference in the look of the appeared to have wear spots on the edges of the links and on the clasp.
Closer examination with a 10x loop proved my suspicions!
Next I tried a magnet ... nothing! Then I decided to try a drop of 67% Nitric acid on the links (without first filing a groove in it) to see how it reacted! The links turned Green immediately!
I've used nitric acid over the years to test scrap sterling silver I intended to buy and have never had any items marked .925 turn green until now!
Armed with this fact I headed to the Jeweller from whom I purchased it and spoke to him in private to discuss my concerns! He viewed the item, seen the markings and said "Who said it isn't sterling? What's Nitric Acid? I've never heard of Nitric Acid! (I found it odd that a Jeweller didn't know what Nitric Acid was ... when he told me he owned a Gold Test kit!). He said "Italian Sterling is high quality and is sometimes coated with Rhodium. Maybe it's the Rhodium wearing off! Let me polish a link then you can test it again!" I took it home tested the link he polished and sure enough it turned green again! I even took an iphone movie of it and showed him that it turned green! Now he wants his own out of Town "repairman" to test it for him, and then even suggested that upon the return of the chain from "his guy" for me to get an independent Jeweller to appraise the chain at his expense!
All of this sounds fishy to me!
Therefore my question is....Has anyone else ever experienced Rhodium wearing off of Sterling silver and reacting that way (bubbling green) when tested with Nitric acid?

"Concerned Consumer"

R Knuth
- Cobourg, Ontario, Canada
April 18, 2013

A. R Knuth,

Green usually means that it's just a silver plate over base metal. Take the time to read through the linked article for further information:

Marc Banks
Blacksmith - Boone, North Carolina, USA

A. Hello R Knuth,

You can see this video:

In this video, you can see that the alloy is very high in copper, so it reacts with nitric acid rapidly and turns it green (from cupric nitrate). If this was real 925 silver, you may see a creamy color in the nitric acid, and not so many bubbles. This is not a failproof test, there are other alloy metals in fake sterling silver, but it is one.

Hope this can help! Regards,

Daniel Montañés
- Cañuelas, Buenos Aires, Argentina

Q. Hi, I have this sculpture of a hindu god which is gold colored outside, and inside it is of a silver color. To find out what metal it was made of I used nitric acid concentrated on the exposed silver portion: the acid was lightly cream-ish but after few minutes the exposed silver portion turned dark grey. When I used the acid on the gold colored part, the acid turned a light green and bubbly but did not discolor the gold portion. What metal do I asuume them to be?

Nirmala raman
- Coimbatore, Tamilnadu, India
August 17, 2013

A. Hi, I do a lot of testing.

Firstly do not buy from eBay , use a reputable jewellery supplier
Second Yes acid does go off.

Testing: First I do by sight (you cannot use acid on other peoples items if in the field)
The scratch stone should be alright; mine has been.
If I am still in doubt I then do a destructive test

If sterling it will come out red.
If above sterling like a lot of Mexican jewellery it will turn bright red.
The less red the less silver content but the piece could still have some silver in it.

Never try to use a magnet to be sure. If you do not know your metals the magnet is one of the worst leads you can get. I use a magnet sometimes but I know my metals and I still make mistakes myself.

I buy at flea markets, etc. Mistakes hit me in the pocket. It is a gamble -- even dealers will try to convince you things are silver or gold when you can plainly see they are not. But a lot of dealers do not know themselves so be careful

Hope this helps


Georgia Reynolds
- Sydney NSW Australia

A. Just as a quickly.

With regard to the comment "Acids go off", can I please make a slight correction--

Nitric acid, properly sealed will stay as nitric acid indefinitely - the same with hydrochloric.

BUT if you combine the two and sell "pre-mixed" Aqua Regia then this DOES degrade over time as the acids react with one another. When I say "over time" within 7-10 days premix can become unsuitable for testing as a worst case and around 3-4 weeks as a best case. Beyond that and you may assume your gold is very pure and in fact it is the case that the acid is weakening.

If you can purchase the two acids on their own and simply "make your test kit with one drop Nitric and three drops hydrochloric" each time you need a few more drops of solution and your unmixed acids (if you keep them stoppered gas tight) will last indefinitely.

Do NOT store aqua regia in a gas tight bottle though as although it will outgas faster, it will then be less likely to be explode or generate other nasties - nitric oxide, chlorine, nitrosyl chloride etc.

For testing silver - you need a different solution but one that is also cheap and easy to make (chemicals should be found easily if you do some searching...)

1g of potassium dichromate (can still be found but getting harder, get some while you can).
Add this to 8 ml of distilled water and then, with care, add 22 ml of concentrated nitric acid. This is also called "Schweters testing solution"

File a notch in the piece to be tested.
Apply a drop of the solution you made above.

- Pure silver turns bright red
- Silver (Stirling Silver 92.5%) turns dark red
- Silver (80%) turns brown
- Silver (50%) turns green

Presence of tin or lead can make this turn yellow and nickel will make it turn blue. Palladium remains clear. Caution that an excess of copper will also make the solution go brown - so use common sense if you think the metal is 80% silver or mostly copper! Brass will make it go VERY dark brown.

Also as a note to the wise, the most conc. nitric acid you can normally obtain is around 67 - 68% and with hydrochloric acid, around 35-37%.

This is already taken into account with the 3:1 Hcl / HNO3 mixing ratio - though Aqua Regia

All the best,

guy Mark Tibbert
- Wellingborough, Northamptonshire, UK
February 23, 2016

Q. Hi. I've just had my white gold chain evaluated. The store did the acid test on the clip (so out of the way) and it came back green and bubbly. Now I've got two questions:

1. Could there be a different test required for white gold?
2. Could it be possible the clip wasn't real? (very expensive chain so would be pretty peeved)

If anyone could help that would be great as at the moment I'm a bit upset about it as my partner spent quite a bit on the chain.


Sorrell Finn
- Staffordshire, United Kingdom
August 21, 2013

A. Hi Sorrell!

I am sorry, but your piece is a fake. Green implies copper, and bubbling implies NOT gold. The nitric acid test is generic for precious metals.


Daniel Montañés
- Cañuelas, Buenos Aires, Argentina

A. Sorrell,
It's possible that the clasp is not a high purity gold or a different metal and perhaps the chain is still authentic. Gold clasps are used in many cases but if the clasp is another metal it tends to be more sturdy, especially if the chain is high K. If the clasp is marked as gold of a certain K, that is a bad sign, it should not be marked as such if it is testing negative.

blake kneedler
Blake Kneedler
Feather Hollow Eng. - Stockton, California

Q. I tested a yellow gold pin. When I scratched it on the stone it was a silver color and did not dissolve with 14k acid test. Is it white gold under a layer of yellow gold?

Joseph Cancino
- Lake Eksinore, California
April 23, 2014

Q. I have this silver creamer dish. I made a deep groove in it with a file. I put my silver acid tester on it and it turned a creamy color then to black. What does that mean?

Tarah joans
- Kelso, Washington Usa
February 28, 2015

Q. What does it mean if it does not bubble green, but solution turns blackish?
My solution is good - I tested a piece of 950 - bright red.

Pam Bryant
OLD TO NEW - Guntersville, Alabama, USA
July 2, 2015

Q. Let's keep it simple. Bought silver testing bottle on eBay and it worked on Monday perfectly.

Then 3 days later tried on another pile of silver purchased and EVERYTHING turned light green!

Retested on items that stayed dark red and they also turned green.

Do you need to order a new bottle every time you open one ?


Timothy Judge
- Hilton Head Island, South Carolina
August 19, 2015

A. I use a commercial silver tester from amazon, a small bottle of dark liquid. It works for about a year, then DOES go stale, showing no reaction at all. I rub the test area with a gray eraser first.

With fresh solution, silver turns shades of red, depending on how much silver there is. If there is any red, I'm happy. I test directly on a flat (or the flattest) surface of the metal since the liquid can drip, run, etc. Also since this is acid, albeit weak-ish, watch you fingers and test only over a junky surface not painted, etc. I keep a wet towel nearby.

If suspicious of silver plate, scratch a good THIN notch in the piece and test with a small drop of solution (got this from a jewelry book).
ALSO: look at the edges where wear might be, as in a bracelet with angles rubbing against each other. A golden tone is probably brass or copper underneath with wear in the silver plate (!)...of course a wipe with a good silver cleaning cloth first sometimes gets rid of the "gold" which could just be tarnish.

Mizar M24 Gold Tester
on eBay or

(affil links)

For GOLD, I use a small machine: MIZAR M24 [on eBay or Amazon] , which is pricey, but I've had it for years. It also requires a liquid which goes stale after about a year or so.

Both liquids depend on how often you open them. I open them ONLY when I'm ready to use, then quickly close, AND put into a second tight container...both can last more than a year (rarely).

The Mizar is extremely accurate, but you have to follow directions. Considering how expensive gold is now, frankly, I think spending a bit more to test for it is worth the cost.
Also, eventually (after years), the well with the metal in the Mizar which has to be cleaned (scrupulously) will wear out, as mine is now.

Oh, and after testing silver, don't delay wiping off the acid. I rub it with a gray eraser and then sometimes a silver cleaning cloth. Sometimes it requires silver polish, and sometimes the gray spot left after the acid needs to be buffed by machine.

Been doing this for years with about 95%+ accuracy ... my only errors come when I don't realize that the solutions are shot. But then I just go to a known entity to verify the quality of the solution and know to buy a new one.

PS: If the Mizar shows a low reading but the metal looks good, it "might" be Palladium (a bonus). The excellent instructions address this.

Also: Beware of "alpaca" for Mexican material. Alpaca looks pretty good like silver but has NO silver in it. It is often marked, but often not. With practice you can almost tell by just looking and handling it.

And "German silver" is another stinker: no silver in it ... everything but the kitchen sink, but no silver.

Zoed David
- Yonkers New York USA

Q. Here's a different situation.
I have been employed as a precious metals buyer and have considerable experience with testing solutions and technique. As a lapidary I have an abundance of specimens picked up from various places that are unidentified. But that doesn't stop me from slicing them up and giving them a polish. I recently slabbed up a couple "quartz-y" rocks and noticed patches of gold metallic material. Having nothing but silver testing solution on hand I put a drop on one of these patches. No effect on most of the patch, with the exception of very small pin points of blood red indicating high grade silver. My question is: is this a reasonable test that is determining that these patches are indeed gold with trace amounts of silver? No other part of the matrix/quartz material reacted in any way, and after rinsing you couldn't tell the acid had ever been there. Thanks for any response.

Saylor Loft
- Grand Rapids, Michigan, USA
January 13, 2016

Q. Can red gold be tested with the same acids that yellow gold is tested with?If yes what colour would the acid make on the red gold?

Millecent Skippers
- South Africa (Cape Town)
January 8, 2017

Red to black then grey

Q. I tested some sterling sheets that I bought. The filed notch first turned dark red, then black and as the acid dripped across the piece of silver, it was black then left a grey mark on the silver.

Question: is this normal or should it stay red indefinitely?

Carole Warner
hobbyist - Sarasota, Florida
August 28, 2018

A. I do not have any problems with the [brand name deleted by editor -- huh? why?] test kit solutions I've used at all. I use a loop magnifier to see the reactions and they are readily visible that way. The angle of light, the best being natural light from a window, is also important. In particular, Sterling silver turns milky with the other instruction colors being spot on for period/age of pieces of jewelry and buttons. Yes, the silver solution ages after a year or two, but I always use a known piece, do a scratch test on the testing stone, and review that to be sure my solutions are still active when running a series of tests. one mentioned here that Rhodium, often used in jewelry and buttons, does not react at all in acids and that it is also impervious to platinum solution. Rhodium is bright silver in color and seems almost artificial and can be made into rather thin materials. I just found a set of two gorgeous impala designed "picture" buttons that retain their lustre and are almost certainly Rhodium as per the above. I buy a new kit after 2-3 years just to be sure and this has been fine and not resulted in any issues when I've sold on EBay with notations about the test kit results included in my descriptions. The scratch test on the stone does no harm. Shake the bottles before use.

G.S. Tucker
- Miami, Florida, USA
October 22, 2019

Q. I was testing a piece of sterling silver and the acid turned a dark reddish orange color almost like dark blood is this normal or is my piece of silver fake.

Jimmy Presley
- Boston Massachusetts
December 18, 2020

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