Q: Expense aside, is there any reason to use white gold instead of platinum for jewelry?
A: As a pure or nearly pure noble metal, platinum is much less likely to be chemically or allergically reactive to the body. So the chances of irritation are much less. As the main whitening agent in most white gold alloys is nickel, to which many people are at least slightly sensitive, this can be a rather important difference in itself. Platinum is denser and stronger than white golds. This means that settings can be made of thin, seemingly fragile constructions, and still have the needed strength and integrity to securely hold stones or jewelry together. Its density and strength combine as well to make it remarkably resistant to abrasion.
This doesn’t mean it is scratch-proof; what it means is that an abrading particle creating a scratch on platinum tends to plow a furrow without actually removing material. Over time, Platinum simply doesn’t wear away anywhere near as fast as white gold or other gold alloys, despite the fact that the actual surface hardness and stiffness of the white golds may seem much higher. So jewelry made of platinum simply lasts longer—sometimes a whole lot longer. There are a lot of pieces of jewelry inherited from grandmothers out there, made of platinum, which have survived in reasonably good shape, despite lots of loving use, since the early part of this century. Very little white gold jewelry has lasted even close to the same way, and generally what has done so wasn’t worn much.
I generally figure that platinum jewelry has about three times the lifespan, in the same conditions, as a similar piece in white gold. While platinum’s tensile strength and resistance to breaking exceeds that of gold, it isn’t actually as stiff (for normal alloys). Unlike white golds, which even when annealed are slightly springy, platinum is a “dead” soft metal, which means it has little spring-back at all when bent. For setting stones, this is wonderful. You push a prong or a bezel over the stone, and it stays where you put it, without springing back just a little. This means that there is no need to bend a prong a little too far to get it to end up in the right place, or to otherwise have to fight with the metal to get a stone properly and safely set.
In short, setting stones in platinum is less risky for the setter, and it makes it easier for the setter to use heavier prongs or bezels as well, when the design would benefit from it. You can set fragile stones more securely, and with less effort, in platinum. They are safer when set, more secure, and the setter is less likely to have any problems getting it that way. And then, after all that, the setting will last, instead of wearing out in 7 to 10 years, as so many white gold ones seem to do.
By the way, this lack of springiness normally associated with platinum isn’t a completely sure thing. Kretchmer and Nissing worked out the requirements for an alloy that would, with proper heat treatment, produce a very serviceable spring. This allows them to build proper tension style settings. These settings work as compression springs, clamping a stone in place with a good deal of pressure from spring tension. Here too platinum excels, making a setting that can keep its strength and spring and durability far longer than any similar white gold one. So far, though, the alloy is a proprietary one, so don’t ask me for details. I believe Mr. Kretchmer is planning to license the alloy to a commercial metals supplier, but I don’t think it’s yet available.
The color of platinum is its native color, and is not due to minority additions to the alloy. So you don’t have the problem with surface depletion of the more reactive nickel that you get with white gold, which gives a white gold piece a dingy, slightly yellowish look needing to be re-polished to restore the color after pickling. Also, platinum’s basic color is a darker, grayer white. This happens to be very flattering to diamonds and other gems, making them look all the brighter; yet the basic white/gray color of platinum does not interfere with the gem’s color. At the same time, the darker, grayer color of platinum also contrasts better with the yellow colors of gold, so two-tone designs can be quite dramatic.
The heavier density of the metal can give a very satisfying weight to a piece of platinum jewelry. Of course, some people prefer a light feel, and the heavier weight does mean that since the metal is sold by weight, the cost is higher as the weight goes up, more than with gold. It costs more as well, because it’s used nearly pure, with usually only 5 to 10 percent alloy added. And the alloy as often as not is another platinum group metal. Iridium, for example is just as noble as platinum, and is just as costly, if not more.
With gold alloys, only a certain percentage (about 58% for 14K, or 75% for 18K) is actually gold. The remainder of the weight is copper and silver and other cheap metals, lowering the cost of the gold alloy. Because platinum melts at a much higher temperature than gold or silver, working with it requires different tools and skills, and normally a greater degree of skill and workmanship than gold. A platinum piece will take longer to make than a gold one as well.
All this adds to additional increased cost over gold jewelry. But it also means that most platinum jewelry has been made by better skilled smiths than much commercially available gold or silver jewelry. Obviously, this is a great generalization, since there are also a great many very fine gold and silversmiths out there. But it seems as though there are fewer platinum-working “butchers”. Platinum jewelry is more “exclusive”, and pieces made in it tend to be made right in the first place. It’s much less likely to be treated with the “per gram” commodity-oriented mindset that characterizes the marketing of many gold items.
by Peter W. Rowe M.F.A., G.G.