Platinum: Durability vs. Scratching (and Some Polishing Tips)
Jurgen J. Maerz • Director of Technical Education, Platinum Guild International USA
 

Introduction
One of the most frequently asked questions about platinum jewelry concerns scratching. It seems the consumer equates durability with scratch resistance and is then disappointed when the platinum jewelry scratches and shows signs of wear. Let me say that all metal scratches: from the finest steel to the finest platinum, no metal is immune to scratching. There are, however, various alloys that have different hardness and thus a greater or lesser scratch resistance.

In the USA, the most commonly used platinum alloys are (compositions in parts per thousand):

• Platinum 900 alloyed with 100 parts Iridium -[Pt900/Ir]
• Platinum 950 alloyed with 50 parts Iridium - [Pt950/Ir]
• Platinum 950 alloyed with 50 parts Cobalt -[Pt950/Co]
• Platinum 950 alloyed with 50 parts Ruthenium -[Pt950/Ru]

Properties and Durability
The hardness of these alloys is typically measured in Vickers Hardness (HV) The Vickers system is a means of determining

Platinum Guild International USA 2004   All Rights Reserved

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