What exactly is 925 sterling silver?

Early metal smelting techniques had no real mechanism to purify silver beyond the "score" limit of 92.5. It is a museum conservation trick to detect the "trace metal " comntent of silvewrae in orderf to determine its authenticity. GOLD was a a coomon trace element of about 0.5% and would leave a representative spectral line in a technique called "Energy Dispersive X-Ray SPec" (or EDAX). Much colonial silver has been shown to be ""fake" because its trace element components were not there. The DUpont collection has several pieces of fake silver detected thusly

Modern silver can be smelted almost 100% purity. With no trace metals, the "antique" piece of Revere ware that you own, may just be a carefully made knock off. I A Dupont had amassed a huge collection of colonioal silver and the estimated fake silver is almost 80% of the pieces. So , purer, in this case, is not better.

Hmm, someone already had the definition. The term comes from the old coinage and 92.5 is the alloy percentage. Copper is the most used temper but the smaller percentages of trace metals always havehelped ID the history of the alloy.

I don't know the context for your question, but in the 12th century, the term "sterling" silver referred to silver alloy smelted in Germany, in an area known as Easterling, which was reliably 92.5% silver content, and was considered "coinage grade" silver. Henry II Plantagenet used "Easterling" silver for the silver pennies he issued in the latter half of the 12th century. These coins are now known as "Tealbay" pennies, because a large hoard of them was found at Tealbay in Lincolnshire in the early 19th century.

There is more than one derivation offered for the word sterling, and although the one i have given is probably the majority opinion, that does not mean it is correct. It has also been alleged that a bird, a starling, was shown on some of Henry II's coinage (i know of no examples, which means nothing), and alternatively, that stars were stamped on coins in the reign of Richard, son of Henry, and that the word derives fromMiddle English sterre, meaning star.

Whatever the actual derivation of sterling is, the term sterling silver is firmly wedded in English coinage to 92.5% alloyed silver.

Yep, I've always known it to be in reference to Easterling Silver, although the other stories are quite quaint and romantic I suppose. Here's a bit more......

http://www.harlequinbeads.com/cgi-bin/beads/library/article.html?article=LIB00070

Trying to find a piccie of the coin or coins in question, I stumbled upon this little gem of a coin website.....

http://www.coinoftheyear.com/-31.php