Do-it-Yourself Diamond Tests – Myth & Fact

Myth: Use a jeweler’s loupe to examine a stone. A real diamond will have inclusions. A “fake” diamond will be perfect.

Fact: Most consumers have difficulty using a loupe and spotting inclusions: unless you have some experience looking at diamonds, the reflections and facet junctions can make it difficult to see small inclusions. Also, some diamonds are flawless and you will see no inclusions!

While it’s true that most diamonds, as products of nature, will have inclusions, it is a myth that diamond imitations, whether they are natural or synthetic, will not have inclusions. Inclusions are the result of a gem’s crystal growth process. 

Synthetic diamonds are not imitations. They are real diamonds.

Synthetic diamonds are also man-made and have the same properties as natural diamonds. Synthetic diamonds are real diamonds. But the price difference between lab-grown and natural diamonds can be considerable. You cannot spot a synthetic diamond by looking at it through a loupe. The only way to tell is by laboratory testing.

Myth: A real diamond will have sharp edges, a “fake” diamond will not.

Fact: This is only true for imitations that are made in a mold, like plastic (and some glass). A natural diamond will have sharp edges, but so will synthetic diamonds and any gem material used to imitate diamond. In addition, any gem, natural or synthetic, can have abraded facet junctions (the line where two facets meet) caused by damage or wear and tear.

Myth: You can spot a real diamond by the quality and metal of its setting.

Fact: While natural diamonds are often set in gold or platinum, the metal alone is not a definitive clue. Because of the high cost of gold and platinum, diamonds today are sometimes set in silver metal, too. Antique jewelry can contain diamonds set in a mix of gold and silver.

The style of the setting is also not a good clue. Diamonds are set in a variety of mountings. And a poor quality setting does not necessarily mean the diamonds aren’t real. The quality could just be a sign of general wear and tear or work done by an inexperienced jeweler.

Myth: Rub the gem with sandpaper. A diamond won’t be scratched.

Fact: This is a destructive test and should never be used! The grit on sandpaper usually has a hardness between 7 and 9 on the Mohs scale, so using sandpaper on material softer than the grit will damage it. You risk not only scratching the metal if the stone is set, but also abrading the surface of the gem and diminishing its value.

Myth: The fog test: Breathe on the gem. A real diamond will not fog.

Fact: This test cannot be replicated with consistent results. Internet advice doesn’t tell us how long one must breathe on the gem to see results. Nor does it tell us how large the surface area of the gem needs to be so that you can actually see the fogging. Synthetic diamonds and natural diamonds will react in exactly the same way. Ambient humidity might also affect your results.

Myth: If it sparkles, it must be a real diamond.

Fact: Many consumers use the word “sparkle” in a very generic way to describe the overall visual effect of a faceted gemstone’s interaction with light. To an untrained eye, almost any faceted gem like synthetic moissanite, synthetic cubic zirconia (CZ), or a colorless natural zircon will sparkle.

On the other hand, an emerald cut diamond does not sparkle like some of these round brilliant diamond simulants.

When gemologists refer to a diamond’s sparkle, it means something very specific: scintillation. In addition to sparkle, scintillation also refers to the pattern of light and dark areas caused by reflections within the diamond.

Myth: The newspaper test: You can’t see the type through a real diamond.

Fact: This is another problematic test. The logic behind it is that a well-cut modern round brilliant diamond is highly refractive, meaning that as light passes through it, the light slows down and bends. As you look through the diamond to the newspaper, the refraction causes a visual distortion, making the newsprint unreadable.

There are no easy and reliable at-home tests that will conclusively tell you if your gemstone is a natural diamond or some other material. One thing is for sure, at Karat World, we guarantee our patrons that we only use natural diamonds to maintain our high standard and service in this industry.

Sourced: GIA,