Things to know about white gold
If you are considering a white gold engagement ring, there are issues you should know about: A subject that is not often discussed or publicized is how white gold jewelry is typically made.
Gold in elemental form is yellow; to make it white, it is mixed with a white metal. Nickel is the metal most commonly used for this purpose. It does a fairly good job of whitening and it is very inexpensive. But it doesn't produce a completely white metal--there are hints of yellow showing. So commercial manufacturers plate the item with rhodium, which is very white and very hard. However, this plating is very thin and will wear off in time, showing the more yellow metal underneath. When this happens, the item is often given another plating.
So durability is an issue. But a bigger issue is the negative ecological impact connected with the plating process. For details, do a search on the internet.
If you want an item of white jewelry, a better solution is to use palladium or palladium alloy metals which have no nickel in them. Palladium is a white metal in the platinum group of metals and it mixes very well with gold. The resulting color is a bit grayish, like platinum, but very beautiful in its own right. Here's a cuff bracelet made in 18K palladium white gold with a matte finish:
and here's a pair of earrings in the same metal, but polished.
Palladium metal avoids the issue of plating and is therefore a much better choice for a white gold jewelry item. For these reasons, I use Palladium and Palladium White Gold exclusively in my white gold designs.