Monday, July 25, 2011

The Truth About Platinum

So a few years back when the hub and I were ring shopping I heard all sorts of crazy conflicting reports about Platinum. I had my roommate who had what was once a beautiful platinum class ring that was so scratched up it was hardly identifiable. I had jewelers who told me it was so hard they cussed every time they had to work with it. And other jewelers who said it was so soft that it scratched deeply and every time you buff out the scratches you lose a little metal. Buff 4 or 5 times and poof your super expensive ring is gone.

Needless to say I was confused. At the time I just decided to go with white gold which is not only cheaper, I love that you can replate it repeatedly with rhodium, there by practically eliminating the metal loss problem (ever seen how skinny the bands get on little old ladies rings) and making your ring look brand spanking new every time you do it (sweeeeet).

But I still wondered about Platinum and its apparent case of multiple personality disorder and the further I got into jewelry design and learning about different metals the more I started to understand. So here's the deal:

In the US, like gold, the platinum content of an alloy only has to be 50% platinum to be called platinum. However, gold is a VERY soft metal naturally (2.5 on the mohs scale). People alloy it for the purpose of making it harder (its not good when you can squish your ring on accident).

Platinum on the other hand is naturally a VERY hard metal (4.5 on the mohs scale). That might not sounds like a big jump from 2.5 to 4.5 but for perspective the Mohs scale goes from 1 (talc) to 10 (diamond) so every step on that scale is a BIG step. In our terms its the difference between being able to dent gold with your fingernail and hardly being able to bend it with pliers. Yeahhhh. Big difference.

So if platinum is SO hard why the bizarro rap? Because platinum gets alloyed for 2 main reasons: 1. Its so dang expensive that mixing it with other metals lowers the cost and 2. It makes it soft enough that jewelers can actually work with it.

However, there are all sorts of combinations you can use when making alloys and its pretty safe to assume that everything they're mixing with that platinum is probably softer than it is. So for the most part the lower the platinum percentage, the softer the metal.

Here's the legal terminology (according to the FTC guides):

Platinum = 95% pure or 950 parts per 1000 and should be marked 950Plat.

Traditional Platinum ≥ 85% pure or 850 parts per 1000 and should be marked 850Plat.

50-85% pure = Must disclose full composition including percentages of each metal contained (ie 60% platinum, 35% irridium or 600Plat350Irid).

If it is <50% or 500 parts per 1000 Platinum it MAY NOT be called or identified as Platinum.

My personal verdict: Don't go lower than 850Plat and you should probably be okay. Purer is better (and MUCH more expensive). So if you can't afford the really pure stuff, I'd stick with white gold and save up for your next ring upgrade. ;)

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