Platinum Selection Issues

Until fairly recently, platinum jewelry was generally fabricated in an alloy of 90% platinum and 10% Iridium, which was and is an excellent all-around material in terms of workability, color and durability. This changed in 19?? when the FTC? Issued guidelines dictating that only jewelry containing over 95.2% pure platinum could be marked platinum (PLAT) without a qualifying percentage (such as PLAT 90). This resulted in the development of a number of different 95% alloys. We cast all the major alternatives, in addition to 90Pt/10Ir.

Available Platinum Alloys

  • 90% Platinum, 10 % Iridium - The only thing wrong with this metal is the stamp. It is white, casts wells, works well and wears well. The only limitation is that you can't stamp it PLAT (without the 90 qualifier).
  • 95% Platinum, 5% Iridium - This metal is white, casts well, but is very soft. It is completely unsuitable for settings or light pieces, and even heavy pieces show wear rapidly. Still, it is the metal we cast the most.
  • 95% Platinum, 5% Ruthenium - The Ruthenium alloy is gives the Platinum a very slight gray color. The metals casts and finishes reasonably well, and is very durable.
  • 95% Platinum, 5% Cobalt - This metal is very slightly blue and is slightly magnetic. We cast Pt/Ru only on special order.
  • 950 Spring Platinum - Very difficult to cast and finish, but the only alloy suitable for tension mounts.

Artistry of Gold     •     635 S. Hill Street, Suite 709-710     •     Los Angeles, CA 90014     •     213.688.0113