To find jeweler trademarks, use a jeweler's loupe to inspect metal jewelry underneath a stone's mounting, inside the band of a ring or near the clasp of a necklace. The Antique Jewelry University's online encyclopedia provides pictures of many jewelry trademarks, and the 925-1000.com features pictures of silver marks.
Jewelry may bear markings for its purity, trademark, date created or townmark. Though some countries require jewelers to stamp or engrave a trademark, or maker's mark, on all gold and silver products, the United States only requires jewelers to mark gold and silver for its purity value. Many manufacturers, however, such as Tiffany & Co., seal their creations with their name.