The most common markings on silver, gold and platinum jewelry indicate how much of the precious metal in incorporated into the piece. For silver, the markings 925 or .925 are common. They both indicate the piece is made of 92.5-percent pure silver. Other common silver markings are 99.9, 81.3 and 80.0.
Gold jewelry markings typically denote the karat rating, with 24 karats indicating 100-percent gold. Other common gold markings are 21, 18, 14 and 10 karats. European jewelers base their system on a 1,000 mark scale, with the 1000 fine mark corresponding to 24 karats.
Jewelers use a 1,000 mark scale for platinum. The mark Pt1000 indicates 100-percent purity. The "Pt" can come before or after the number, or jewelers can use the marking "Plat."
With antique jewelry, the hallmarks depend on the country of origin. For example, in Great Britain many jewelers used a system of symbols to mark the town origin of their pieces. The town mark typically came from the city's herald. The Dutch combined a town mark with another symbol to indicate the metal's purity.
Other marks include designer, tally, retailer, duty and import/export marks.Learn more about Jewelry & Watches