Good day everyone,
As you may know the Federal Trade Commission has revised the
quality marking regulation for Platinum, and I thought this would
be a good place to share this The rules are based on
a minimum of 950 parts per thousand PGM’s.
PGM’s are Platinum Group Metals. There are six of them.
Platinum, Iridium, Ruthenium, Palladium, Osmium and Rhodium. So
in order to refer to a piece of jewelry as Platinum it has to be
made of 950 parts per thousand PGM, of which at least 50% has to
be Platinum itself.
To stamp it PLATINUM or PLAT, the entire 950 parts per thousand
or better need to be all Platinum.
When it is 950/1000 Platinum it can also be stamped Pt950 or
950Pt or 950Plat.
There is also a Pt900 or 900Pt or 900Plat which is used for the
very common 900 Platinum 100 Iridium alloy. In the past you would
see the stamp IRIDPLAT in jewelry made of this alloy combination.
Since there is no tolerance for solder in this regulation,there
is also an alloy at 850 parts per thousand Platinum. As platinum
solder contains usually no more than 15% platinum, items such as
soldered chain product would end up being 850. With the laser
method of fusing the links it is now possible to make high purity
chains. These soldered chains, however, would be stamped Pt850,
850Pt or 850Plat.
If an item is made of even lower purity ( under 850 /1000) the
law requires you to identify the parts per thousand of the other
PGM that will make up the 950/1000. For example 600Pt350Ir or
600Plat350Irid for an Platinum Iridium alloy of low purity.(
this is not a common alloy but just a stamping example)
You may wonder what the remaining 50/1000 are for. Well, there
are high purity alloys in Platinum that use this 50 parts to
create special mixes for special purposes.
Pt950 with 50 additional parts Cobalt make an excellent casting
alloy
Pt950 with 50 additional parts Tungsten make a springy metal
Pt950 with 50 additional parts Gold can be aged and thus made
very hard etc.
With the ever increasing popularity of Platinum I feel this is
every bench jeweler can use. For further questions
or help with working with this exiting metal, don’t hesitate to
call out Platinum Hotline at (714)760-8882
To request free technical literature, send a fax on your company
letter head to PGI USA (714)760-8780
Have a platinum day
Jurgen J. Maerz
Manager of Technical Education
PLATINUM GUILD INTERNATIONAL USA