-- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

on this site
current topics
topic 18907

Need complete gold specific gravity table


After I melted my unused jewelry and make it into gold bar, how do I know how much percent that gold is it? I use specific gravity theory. And I need the table of specific gravity. eg. 19.33 for 99.99% of gold ...I need complete table from 10% of gold until 99.999% of gold.


Jendy M [last name deleted for privacy by Editor]
- Indonesia

Rare Earth Magnet


A. This method will not work if more than one alloying element is present.

Different alloying elements have different SG's, e.g., 8.90 for cobalt and nickel, 8.94 g/cc for copper, 10.49 for silver, 12.0 for palladium, 12.4 for rhodium, 21.45 for platinum, etc. It is possible for alloys of different gold concentrations to have same SG, and for alloys of same SG to have different gold content. An alloy of 83 vol.% platinum and 17 vol. % copper will have roughly the same SG as 100% gold. Even knowing the composition (wt.% or at.%) of a multi-component alloy, it is difficult to accurately calculate the exact SG because non-ideal thermodynamic interaction of atoms will affect the volume. Porosity is another problem.

From an Internet search, you can find data for simple alloys such as gold-silver and gold-copper. But because of multicomponent effects noted above, 9 carat gold has SG range 10.9-12.7, 18 carat yellow gold 15.2-15.9, 18 carat white gold 14.7-16.9, 22 carat 17.7-17.8, sterling silver 10.2-10.3.

The World Gold Council ( describes methods of analysis under heading assaying. The density method is listed as poor for accuracy and only for binary alloys.

Ken Vlach
- Goleta, California
contributor of the year honored Ken for his countless carefully
researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work
which the finishing world continues to benefit from.


A. I have been testing items for gold content for many years now and found using a grain scale a fairly accurate specific gravity can be attained.enough so that the tester will know if the item has gold in it. Like the last article stated without knowing what other metal has been used it is hard to judge carats. I assume copper as second metal being most common and if my test comes back with a sp over 12 I am reasonably certain it is gold most tests of jewelry have a sp of 12 to 14 meaning gold in the range of 10 to 14 carat. Very seldom have I been mistaken. Tonight I just finished a sp test on a ring with the sp of 15.3 tomorrow I will find out if it 18 carat gold as my test showed. It may not always work but a sp test is an inexpensive means of testing chemicals or damages to item just a grain scale thread and a glass of water.

Robert S [last name deleted for privacy by Editor]
- Tujunga, California, USA

July 30, 2012

Q. Dear All,
I have been asked to develop a software to test gold purity. We don't know anything about possible metals and their combination alloyed with that particular gold bar. But still they are using this software for testing gold purity commercially in Gold test laboratories. I am sending you few calculations.
First Calculation:
First Weight (Dry Weight) 7.808 gm
Second Weight(Suspended spring scale in water) 7.384 gm
Total Impurity 0.3368 gm
Total Pure Gold 7.4712 gm

Second Calculation:
First Weight (Dry Weight) 10.3340 gm
Second Weight(Suspended spring scale in water) 9.783 gm
Total Impurity 0.3365 gm
Total Pure Gold 9.9975 gm
Carats: 23.2185K

Any help will be greatly appreciated.


- Pakistan

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site


Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.