A discussion started in 2010 but continuing through 2019April 25, 2010
Q. I received a simple "silver" cross as a birthday gift from sister way back in the 70's. It is stamped "Sterling Theda" on the back. Since we were both college students at the time, I assumed that this meant that it was some type of ersatz silver-looking substitute that contained some silver. However, I did understand that the term
"sterling" implied a guaranteed % of real silver. Over the years it blackened slightly at the edges that wore against my chest. After recently ruining the previously replaced chain by using pure sulfur soap on my face in the shower, my wife took it to a jewelry store who cleaned it free of charge to the original shiny silver appearances of both chain & cross. Now I noticed that the edges are blackening slightly again. I became curious as to what exactly "theda" meant/was. A search of the internet did not reveal a definitive description but some descriptions of old jewelry for sale on Ebay seemed to make the connection with Rhodium by stating that the piece for sale was stamped "Sterling Theda" on the back & including "rhodium coated" in the description.
What is the derivation of the stamp "Sterling Theda" on the back of jewelry? Is it Rhodium-coated sterling silver? Is "Theda" a proprietary term used by one company years ago?
Personal - Phoenix, Arizona, USA
May 11, 2010
Theda is a brand name made by the Ideal Mfg Co. in Providence R.I. The company started doing business in 1921. It very well may be an art deco piece. Sterling was sometimes used as a hallmark in the US instead of .925 (fineness). My best guess is that it is sterling silver, otherwise it would be stamped "silverplate". As far as the cross turning black on the edges, may have to do with your body chemistry.
process engineer - Malone, New York
May 21, 2010
Thanks, Mark.Rich Schur
- Phoenix, Arizona, USA
March 4, 2019
Q. My name is Lawrence, I have a similar piece of jewelry that is a cross within a cross. And it is stamped "Sterling Theda" as well. I am curious if someone could help me figure out it's age and origin. I would very much appreciate it. Thank you for your time and consideration in this matter.
- Higbee, Missouri
A. Hi Lawrence. Three of this item are presently on sale on Ebay, from $28 to $43. Sorry, I don't know the history.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"
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