We exclusively use 95% platinum ruthenium because it offers the best combination of color, hardness, and workability. It also may be stamped "PLAT" according to FTC guidelines.
One of the great benefits to pure platinum is that it's "hypo allergenic." Well, technically, it's non-reactive, therefore, alloy choice becomes critical in keeping platinum jewelry "non-reactive" or "hypo allergenic." There are several alloys out there that make platinum jewelry reactive - in otherwords, people develop skin irritations. The most notable "reactive" alloy is platinum/cobalt. This alloy was developed with the intent of making platnium easier to cast (but with little concern of the loss of benefit to the end customer). It also adds magnetic properties to platinum...not fun when trying to separate steel from bench-sweeps!
Another reactive alloy would be platinum/copper: the biochemistry of certain people causes them to "leech" copper out of jewelry alloys. Although platinum copper is not as common, it's out there. For more information from the Platinum Guild, click here and here.
With the economy slowing, people are getting more resourceful and we're getting more requests to cast scrap platinum. Retail customers are even going into jewelry stores requesting (and even insisting) that their custom jewelry be made with their own metal.
Before we go into the pros and cons as to whether this is a good idea or not, let's address the most important factor:
Is there enough metal to cast?
In our platinum casting process, we've found that there's a "threshold" for the minimum amount of metal needed to cast: not less than one ounce (31.1g). Casting successfully requires that there be enough energy in the casting system to keep the metal from freezing before the mold is filled, and since platinum freezes extreemly fast, messing around isn't worth it (inotherwords, you're welcome to hire us to prove what's already been proved if you like to gamble and lose!). If you have the minumum amount of scrap platinum for casting, then keep reading...