You can trust a diamond tester as a helpful first step to rule out obvious fakes like glass or cubic zirconia, but never rely on it solely, especially for high-value stones, because modern simulants like moissanite can fool basic thermal testers, and the testers themselves can malfunction due to dirt, low batteries, or user error, requiring professional gemological verification for true authenticity. More advanced multi-testers can differentiate diamond from moissanite by checking electrical properties, but professional gemologists with specialized equipment offer the highest accuracy.
Are Diamond Testers Accurate? Diamond testers are accurate in checking diamonds for authenticity. Sometimes moissanite can throw off a thermal conductivity diamond tester because they're similar to diamonds in the way they conduct heat.
Yes, some diamond simulants can pass a diamond tester.
For example, moissanite, a man made gem, may pass as a diamond on a standard tester pen. This is because moissanite also has very high thermal conductivity! Other diamond simulants, such as CZ, will not pass the tester.
Diamond testers have a metal tip at the end of the tester to determine if the stone is a real diamond. It measures thermal conductivity specific to diamonds. The sprung metal tip is pushed against the diamond or gemstone, and the LED reading shows whether the stone is a genuine diamond or not.
If your diamond is authentic, the tester is designed to make a beep-sound or have a small light on the device flash red.
Why Does Moissanite Fool Some Diamond Testers? Moissanite is sneaky. It has a lot in common with diamonds, and one of its best tricks is heat conductivity. Older diamond testers rely on heat to tell if a stone is real, and since moissanite conducts heat almost as well as a diamond, these testers can get confused.
They make great costume jewellery, but they are not suitable for sale in a quality jewellery shop. Sure, they are chemically, physically and optically almost identical to natural diamonds and will look flashy and sparkle well. But there is no soul or identity to them.
The Aquamarine name comes from the Latin word for seawater and is said to calm waves and keep sailors safe at sea. It is sometimes referred to as a poor man's diamond because of the pale color.
CZ will not pass a diamond tester. Moissanite has the highest refractive index in the world, and based off how that chain is shining, it's most likely Moissanite.
No, a jeweler generally cannot tell if a diamond is lab-grown just by looking at it with the naked eye; they need specialized, lab-grade equipment like GIA iD100 or X-ray luminescence (XRL) testers to detect subtle differences in growth patterns, impurities, or fluorescence, as lab-grown diamonds share the same chemical and optical properties as natural diamonds. While some jewelers have machines to test, professional grading labs (like GIA) use advanced methods to identify them, often relying on laser inscriptions and grading reports for confirmation.
The best fake diamonds are cubic zirconia (CZ), moissanite, and lab-grown diamonds. CZ is affordable and looks similar to real diamonds. Moissanite offers great brilliance and durability. Lab-grown diamonds have the same properties as natural diamonds but are more ethical and cost-effective.
Real diamonds don't fog up as long. If you take the stone and breathe on it—whether it's real or fake—it will fog up, just like a mirror. The difference, however, is in how long the fog lasts on the stone's surface. With real diamonds, the fog will disappear quickly because diamonds conduct heat.
Different pawn shops will have different devices on hand that can help not only test if a diamond is real but also how much the diamond would be worth. Diamonds are evaluated on four metrics referred to as the 4C's of diamonds.
The GIA iD100 distinguishes simulated and laboratory-grown diamonds from natural diamonds. It is able to test colorless to near-colorless, blue-to-green and brown diamonds.
Yes! Under most circumstances, lab diamonds test identically to real diamonds when using a standard diamond tester.
How Reliable Are Diamond Testers? Diamond testers are always accurate. However, the thermal diamond testers can be faulty when testing moissanite because it has a similar heat conductivity rate to natural diamonds.
What is Cubic Zirconia? Like lab diamonds, cubic zirconia is also a synthetically created stone, but its crystal structure and chemical composition is completely different. While lab-grown diamonds are made of carbon, cubic zirconia is the cubic crystalline form of zirconium dioxide.
A diamond tester is more accurate than a scratch test.
Once the suspected diamond has been located, press the diamond tester's tip against it. Minerals that make noise and light up are diamonds. If it doesn't, there is a difference between a gemstone and a precious stone.
Because inclusions are more visible in diamonds with larger, open facets, you should pick VS1 over VS2 when choosing diamonds in shapes other than round (particularly in step-cut diamonds such as emerald-cut or Asscher cut).
A 20-carat diamond is quite large, weighing 4 grams (0.2 grams per carat) and appearing roughly the size of a U.S. dime to a bit larger, with dimensions around 20-22 mm long for an oval or about 20-21 mm in diameter for a round cut, though size varies significantly with shape and cut quality.
Gypsum crystals from the Great Salt Lake in Utah have been nicknamed “dirty diamonds.” With a chemical composition of hydrous calcium sulfate (CaSO4 · 2H2O), such crystals are found as floater crystals in clay beds, where they fully form without being attached to matrix.
The answer is that a lab-grown diamond is a real diamond. Compared to mined stones, they're just as beautiful. They have the same chemical and physical properties, features, clarity, color, and size grades and are certified. At the same time, there is a significant difference between lab-grown and natural diamonds.
Costco sells diamonds with a cut grade of Good to Excellent. Although treating diamonds is an accepted practice among many jewelers, Costco only sells natural and untreated diamonds.