Platinum – A Guide to Jewelry Materials

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What are the quality marks for Platinum?

Platinum Stamping: The platinum standard is based on parts per thousand, where 1000 parts = 100%. All platinum alloys are derived from this standard. The two most common platinum alloys found in the US are:

95% Platinum: This alloy is 950 parts per 1000 and 50 parts other metals. Common quality marks are: Platinum, Plat, Pt, Pt950, 950Pt, 950Plat and Plat950.

90% Platinum: This alloy is 900 parts per 1000 and 100 parts other metals. Common quality marks are: 900Pt, Pt900, and 900Plat. Typically platinum is alloyed with copper, iridium, palladium, cobalt, ruthenium, tungsten, gallium or indium. It can also be alloyed with rhodium, osmium or titanium but these are rarely used.

Measuring Perfection

1000 parts = 100% platinum. All alloys are derived from these 1000 parts.

Platinum % Common Quality Marks Alloy Composition
100-99% Platinum Plat; Pt999 999 parts per thousand 1 part other metal
95%  Platinum Pt; 950Pt; Pt950 950 parts per thousand and 50 parts other metal
90%  Platinum Pt900; 900Pt; 900Plat 900 parts per thousand and 100 parts other metals

Facts about Platinum

  1. Platinum requires special skills and tools to work with.
  2. It is completely hypoallergenic.
  3. Platinum is the hardest of the precious metals and it never tarnishes.
  4. Platinum is more resistant to wear and tear than gold or silver because it has a higher density.
  5. A six-inch cube weighs 165 lbs
  6. Platinum has an extremely high melting temperature. In its purest form it melts at 3214 degrees F, almost twice the temperature needed to melt 14 karat gold.
  7. All the platinum ever mined would produce a cube 17 feet on each side, less than 5000 cubic feet.
  8. It takes up to 10 tons of ore to produce one ounce of platinum, more than twice as much ore that is typically needed for an ounce of gold.
  9. Platinum is not susceptible to problems like stress corrosion or stress cracking as can be the case with white gold.
  10. Platinum is resistant to attack from most chemicals.
  11. 1 gram of platinum can be made into wire 2 miles long.
  12. It takes 8 weeks to refine pure platinum from the ore extracted from the earth.
  13. Platinum is used in medicine and industry for its catalytic, physical and hypoallergenic properties
  14. The ultimate stability of platinum over the years is unmatched. It does not wear, and its extreme level of durability offers a profound guarantee of strength and longevity.