Understanding Metal Composition: What Does a 915 Stamp Mean?

Question
What is the composition od 915?

Answer
Dear Donna,

There is not a standard metal quality stamp for 915. However, this does not prevent someone from making and stamping a precious metal with a 915 designation.  

However, only in particular cases is the number enough to identify a metal. For instance, sterling silver carries a standard stamp of "sterling" (or variation of the words) or the number 925. The quality mark 925 is recognized for sterling silver, meaning the metal is 92.5% pure silver mixed with another metal to make sterling silver. The other metal is generally copper but that is not identified in the stamp.

Platinum is identified by PT950 or PT900.  Sometimes with the 950 variety the 950 is the only quality mark and the makers mark is there also, as required by law.

If the 1 in your 915 is actually a 2, then you have the mark for sterling silver. If gold colored but marked 925, it is vermeil, a gold plated sterling silver.

Otherwise, you will need the services of a jeweler who tests metals to determine the metal. Note, if this is costume jewelry, the number is not a quality mark at all but perhaps a style number and there is no need to have the metal tested. If you believe it to be precious metal, call around and find a jewelry business who will test the metal for you.
As I said, unfortunately 915 is not a standard quality mark and is meaningless by itself.

Donna, I have to tell it like it is. Fair enough?

God Bless and Peace.  Thomas.