Platinum and white gold are precious metals that take a high polish. Both metals are durable and hard. Once platinum is bent, it stays in position better than gold. This feature makes platinum the preferred metal for prongs. Which metal you choose for the rest of your mounting is a matter of personal preference, as both metals will yield a lovely, durable ring. However, there are a few considerations you may wish to keep in mind when purchasing your ring.
Platinum and white gold are both beautiful and long-wearing. Platinum is denser than gold, and, unlike gold, the composition of platinum is such that the metal is only displaced when scratched, not lost. The purity of platinum's composition also means it is hypoallergenic and a good choice for those with metal sensitivities.
Unlike gold, platinum can develop a patina, which is a soft, rich surface appearance that occurs with age, similar to a brushed or satin finish. This distinctive finish is part of platinum's charm, however, if you find it undesirable, you can revive your ring by buffing it with a polishing cloth at home, or having it professionally polished by a jeweler.
Platinum and white gold rings are often rhodium plated, which gives them an almost identical bright white finish. The set of two rings in the first photo below are 18 karat white gold and platinum, respectively. The rings exhibit the same luster due to the rhodium finish. However, rhodium wears away with time. When this happens, platinum, which is a naturally white metal, maintains its gray-white color. White gold, on the other hand, may begin to exhibit a yellow tint, and will need to be re-plated to regain its white shine. (Please note that annual re-plating is primarily a consideration for engagement and wedding rings, which are subjected to daily wear. Other white gold pieces may go many years without losing their luster.)*
Most jewelers suggest re-plating your white gold ring once a year. This service costs approximately $60.00 - $120.00, depending on the intricacy of your setting. However, you may find that the finish on your ring lasts for many years.
If you prefer not to re-plate your ring, then a platinum ring (or a yellow or rose gold ring) may be more appropriate. Otherwise, white gold is also an excellent choice.
Photo Gallery: (1) 18k white gold & platinum rings with rhodium finish; the rings exhibit the same bright luster (2) white gold and platinum rings where the rhodium has worn away: the set with the blue stone is white gold, the other is platinum; after many years of daily wear the white gold band has taken on a faint yellow tint and the platinum band has developed a satiny patina.
*It's beneficial to have your fine jewelry periodically inspected by a professional jeweler to ensure that your gemstones are still securely mounted. This is a good time to have your pieces professionally polished or replated.