What does the hallmark 18k 766 mean?
Probably that it was # 766 of an 18k Design.
It should be stamped with a "hallmark." A hallmark for silver should be "925." This indicates 92.5% pure sterling silver. Another hallmark for silver could be "STERLING". A U.S. hallmark for gold would be 10K or 14K or 18K indicating the gold content. Pure 100% gold would be 24K; 10K is 41.67% gold; 14K is 58.33% gold; 18K is 75% gold.
The hallmark for jewelry indicates the person who made the jewelry. Every designer has their own hallmark. You will often see numbers by a hallmark such as 925 which means it is sterling silver or 14k, 18k etc which indicate the amount of gold in the jewelry. Hope this helps. If you have more questions feel free to email me!
It Means that it is made in Peru, of Sterling Silver and 18 carat gold. Pieces typical of this hallmark configuration have a large sterling silver base with a thin 18K gold figure in the center. I've mostly seen this hallmark on Brooches, pendants and a few bracelets. If you search on e-bay you will find a number of items with a similar hallmark listed under "Peru Silver".
In general, 750 is used rather than 18K in Europe. For example, a British hallmark for 18K jewelry will usually have The maker's mark, 750, the assay marks and the date letter. However, not all European jewelry will use millisimal fineness, some still will use 18K instead, however its very rare that US-made jewelry will use 750 rather than 18K.