How can you tell if an impressive-looking rock is a real diamond or just a piece of glass? Harry Levy, president of the London Diamond Bourse, has the experience to spot a fake in a flash. He explains what to look for when you're going jewellery shopping.
Stick to a real dealer
Avoid online sellers who can hide behind an avatar or username. Instead, find a jeweller with a shop to which you can -easily return if you have problems. Research prices by noting down the parameters of a diamond – size, clarity, colour and cut -- and comparing with similar stones in other shops.
Beware cubic zirconia
Synthetic cubic zirconia (CZ) gems are often used as diamond substitutes, but they differ in key ways. "We would spot a CZ very easily," says Levy. "It's much denser than a diamond." It is also very clear. Although this is desirable, diamonds as "white" as CZ are the most expensive. Be wary of gems that look too perfect.
Don't be fooled by moissanite
Another imitator is moissanite. Naturally scarce but easily synthesised, it's simple to spot because the gems are doubly refractive – they split rays of light in two. "If you look at it, you get giddy, because it looks like the edges at the back double up," explains Levy. It also has a hazy effect that makes the stones look greenish.
Spot the telltale signs
Look at the edges of a questionable gem. Are they as sharp as they should be? Does the cut seem odd? There are variations, but a standard diamond is usually cut in the "round brilliant" shape, with 33 facets on the top half.
If you're still not sure, a jeweller's thermal and electrical conductivity tests will identify the pretenders.
This article was originally published by WIRED UK
