Platinum, rhodium and palladian - three of the six memebers in the platinum family - are used for jewelry. The color of platinum is gray-white and resembles polished silver when finished. Platinum is mixed with small percentages of silver or copper and hardens when alloyed with iridium.

The platinum standard is based on parts per thousand, where 1000 parts = 100%. All platinum alloys are derived from this standard. There are two major types of platinum used to making rings and other jewelry:

Platinum - 95%
This alloy is 950 parts per 1000 and 50 parts other metals. Common quality marks you should look for include:

Platinum, Plat, Pt, Pt950, 950Pt, 950Plat, Plat950

Platinum - 90%
This alloy is 900 parts per 1000 and 100 parts other metals. Common quality marks you should look for include:

900Pt, Pt900, 900Plat