Detecting a Lab-Grown Diamond with a Tester

Lab-grown diamonds made using HPHT can be detected as moissanite. Why? 

Lab-grown diamonds can be grown using different
techniques, including the High Pressure High Temperature (HPHT) method, which can
sometimes cause diamond testers, such as the Presidium Multi Tester
or Presidium Diamond Verification, to detect them as moissanite.

 Moissanite (SiC) is a mineral that has a similar appearance to diamonds
and is often used as a diamond substitute in jewellery. It is also considerably
cheaper than natural or lab-grown diamonds. Diamond testers
work by measuring the thermal conductivity of the gemstone. Diamonds have
high thermal conductivity, meaning they conduct heat very well, while
moissanite has a much lower thermal conductivity. However, some HPHT lab-grown diamonds can be
registered as moissanite on diamond testers. This is because the
HPHT process can sometimes leave metallic inclusions in the diamond, which can affect its
thermal conductivity. These inclusions are often iron or nickel, which have a much
lower thermal conductivity than diamond, but one similar to moissanite. As a result,
when a diamond tester is used, an HPHT lab-grown
diamond with metallic inclusions may be registered as moissanite instead of diamond.

 Another factor that can cause an HPHT lab-grown
diamond to register as moissanite on a diamond tester is the
crystal structure. While both diamonds and moissanite are made up of carbon atoms,
their crystal structure is different. The crystal structure of moissanite grown
using the HPHT method more closely resembles that of diamond. This can
confuse diamond testers, because the tester may not be able to tell the two
materials apart. 

From our experience, it is mainly small lab-grown diamonds (HPHT) that are detected as moissanite. For larger sizes above 0.30ct, lab-grown diamonds are reliably detected as diamond on the tester. 

How to easily tell moissanite apart from both natural and lab-grown diamonds: 

– a natural diamond is like a “drop of water” – clear, pure, transparent. Unlike a diamond, moissanite has a slightly hazy (milky) look. With a bit of exaggeration, it’s a bit like pouring milk into a glass of water. 

Other ways to tell a diamond apart from moissanite: 

– a diamond is carbon (C) | moissanite is SiC (silicon carbide)

– moissanite is more colourful (up to 200% more fire than diamond)

– moissanite has birefringence 

– hardness: carbon 10 vs. moissanite 9.25

We have more than 50,000!! diamonds for you to choose from, so we firmly believe we’ll find the right diamond for you. We actively monitor our competitors’ prices and can say that we offer both lab-grown and natural diamonds at the best prices on the market. 

If you’re still hesitant, send us an enquiry and we’ll get back to you right away with an offer you can compare with no obligation. 

We look forward to hearing from you soon! 

If you have any questions about lab-grown & natural diamonds, feel free to write to us at: info@laboratornidiamanty.cz 

Team ULTIMATE-GEMS s. r. o.