White metal used for rings can be either white gold or platinum. White gold is rhodium plated after manufacture to give it a more intense white colour. This plating will wear off over time and will need to be replated with rhodium at your jewellers. On the other hand, platinum retains its colour. Platinum is also harder than gold.
A diamond solitaire ring is the traditional choice for an engagement ring. There are other options available, with the best choice being the one that suits the bride-to-be.
You can get a white gold engagement ring at many online and high street retailers. The biggest misconception about white gold is that it is primarily made of yellow gold.
With precious metal, everything is repairable!
Engagement rings are traditionally diamond so this would be the best stone to have set in a white gold ring for this purpose. If you would like to be less traditional then you could use ruby, diamond or sapphire, either alone or alongside diamond.
Yes, the wedding ring and the engagement ring should be the same metal. You can purchase a set to make the two pieces work together.
You may want to have that ring checked by a reputable jeweler. It sounds like you have a copper ring plated in white gold and the plating has worn off the underside and is oxidizing from the moisture on your finger. White gold is Regular gold mixed with a white metal like nickel to change its color.
Probably 18 karat gold/nickel alloy. White gold is gold mixed with nickel and looks silver.
In short, no, you do not have to have a special ring for the engagement. However, most people buy an Engagement ring for this occasion. Engagement rings are usually made of yellow gold, white gold, or platinum and usually have at least one clear diamond. To see an example of a traditional engagement ring, please see the resources/links section below.
In a store
The 625 which is stamped on a white metal ring means the ring is classified as 15 carats. Jewelers place the marks on jewelry so they can be easily identified.
Yes, they will. White gold is not naturally white like platinum--it is alloyed with other metals and plated with rhodium to give it it's white appearance. The plating on a white gold ring will eventually wear away, and you will need to re-plate your ring to restore it's white appearance, or else it will start to take on a yellowish tint.You should also know that a platinum ring will accelerate the wear on a white gold ring because platinum is a stronger and more durable metal than white gold. The platinum ring will constantly be rubbing up against the white gold ring if they are both worn on the same finger (which is the traditional way of wearing the rings), and this friction will wear away at the plating of the white gold ring.For these reasons, it's preferable to get matching metals for your engagement ring and wedding band.
The finishes that one may get for an art deco engagement ring are gold and platinum to name a few. Many people also like the ring to have an antique style finish applied to the metal.