"WHY IS MY WHITE GOLD RING TURNING YELLOW???"

This is a common question that plagues my store weekly. Not long ago jewelers discovered that yellow gold can be inexpensively turned white if they Rhodium plate the jewelery piece. This process also could be done over small diamonds which also help to hold a small burnished diamonds into place. The problem is that over time the rhodium plating wears off (especially on the shank). Also, if the jeweler applies any heat to the jewelery during the repair process, the rhodium needs to be reapplied. I don't have a clue what the current cost of rhodium plating is because I don't believe in it (there... I said it!). Needless to say, the inexpensive piece of white gold jewelery now cost considerably more to repair than a slightly higher price white gold piece.
Naturally, gold is not found in a white color, so the gold is mixed with different "metals" to give it's white appearance. The following is copied directly from my Mettallurgy of Karat Golds book:
White golds are created by replacing the silver in the traditional gold-copper-silver-zinc compositions used for 14 and 18K yellow gold with nickel. The nickel and zinc present in white golds reduce the red and yellow colors relected by the copper and gold. Unfortunately, this reduction in the red-yellow reflections is no where near 100% efficient and some red-yellows are still reflected. These nickel and zinc additions also do not increase the reflection of the green-blue-violet colors in white light. Remember that silver has a very high reflectivity for all the colors in the visible spectrum. The net result is that nickel white golds can have yellow tint and they are not as white as silver.
NO Jeweler has the right to say that all white gold is actually rhodium plated yellow gold. In fine white gold jewelry, the gold is not rhodium plated yellow gold, although some jewelers will rhodium plate over a true white gold to add brilliance to it's color, and that's fine. Keep in mind however, that if you have an allergy to nickel, you may want to stay away from white gold.

Gold Weight

As a follow-up to the last post, I wanted to explain about DWT. Jewelers measure gold (without gemstones) in several ways, Grains, Grams, Kilograms (kg), Aviordupois Ounce, Troy Ounce, Pennyweights (dwt), even in pounds. We use conversion factors for each. When you see the price of the gold market which changes frequently with the stock market, the price of the gold is per Troy Ounce. I usually weigh gold in grams then convert it to troy ounce. So for example someone brings in a ring with a weight of 3.36 grams, then I multiply it by the conversion factor of 0.03215 = .11 (troy ounce) then multiply it by the current gold market (example: $723) = $79.53
I'm always amazed when someone wants me to appraise an item for more than it's worth. I had a lady come in with a hollow 14k gold bangle bracelet that thought it should be appraised at more than $800. After weighing the item, explaining my mathematics, and showing her how my brand new bracelets sell for far less, she still left in a huff. Well you can't win them all.
So when we say "dwt"this is not gram, or troy ounce, it means pennyweight. Item #62280 on our site is 4.09 dwt. The conversion for dwt to grams is x 1.5551 so this item is 6.36 grams x .03215 (to troy ounce) = .20 x current gold market price (example: $723) = $144.60 Yes, I know this is selling for more than $1000, but don't forget about the diamonds, and also that it's not just a lump of raw gold.
So now that you know what dwt is, and you know that all settings have a dwt, COMPARE, COMPARE, COMPARE. When it comes to jewelry, bigger really is better.