Diamonds and diamond simulants and synthetics have been growing closer in appearance and chemical make-up over the past 10 years. However, simple tests that don't require high-cost gemological equipment can help determine a true diamond from a simulant, synthetic or "fake."
True diamonds and diamond simulants have different weights. For example, a CZ Zircon weighs about 1.31 carats, which is approximately 55 per cent more than a real diamond of the same size. As another example, a Moissanite round brilliant stone of 6.5mm weighs approximately 0.87 carats when compared with a real diamond. For accuracy, use a carat or gram scale.
Using a standard page of text, place the stone or ring upside down on the page, over the text. If it is a real diamond, you will not see any indication of markings on the page beneath, just a light reflection. A simulant or synthetic will show the text or at least a smudged and illegible version of the text.
Hold the stone to your mouth as though you wanted to make steam clouds from your breath on a cold day. Pull the stone away and look at it. If it remains foggy like a bathroom mirror after a shower for more than three seconds, it probably is not a diamond but only a simulant.
Using a jeweller's 10x magnification loupe, check the stone's facets for abrasions. Diamonds will not abrade in this way. If you do not care whether doing so ruins the fake, run sandpaper across its top table. If there are no abrasions, it is a diamond. If abrading occurs, it is probably a low-grade simulant.
Inclusions in a stone, such as feathering or fogginess, natural fissures or carbon speck inclusions, though undesirable in diamonds, are common to some extent, and let you know you have the real thing and not a perfect replica.
Beware and shop around. Simulants, synthetics, Moissanite and poor-quality diamonds generally are sold at 50 per cent of the price of good- to excellent-grade, real diamonds. Price alone creates the greatest draw, but unless you are looking to invest and trade up in diamonds over time, buying a lesser quality or synthetic or simulant stone might be your best option.