| Platinum
Related
Metals and Platinum Purity
You
may hear about the five other metals that are part of the
platinum family--iridiur1 rhodium, ruthenium, palladium, and
osmium--and you may wonder how they relate to jewelry. Rhodium
is used to plate white gold and platinum because it is harder
and more reflective.
It’s
also used to make yellow gold look like white gold and to
prevent silver from tarnishing Iridium (5% to 15%) is usually
mixed with platinum to make it harder and more suitable for
jewelry wear. Ruthenium is occasionally used to harden platinum.
Palladium
is relatively inexpensive and lightweight so it is occasionally
used to reduce the cost and weight of platinum It is also
mixed with gold to form white or brown gold and, at times,
has been used alone imitate white gold. Osmium is the hardest
metal known and is rarely used in jewelry.
Platinum
jewelry is identified by the marks PT, pt, plat, or platinum.
To be called platinum, the metal must consist of at least
85% platinum (many countries such as the GSA. Hong Kong, and
England require 90% or 95% platinum). If the purity is less
than 85%, then the other metals and their percentages have
to be identified when calling metal platinum.
Harder
and therefore
Hardest
metal known
Probably
be better
Chapter
Nine since
|
