Digital diamond and gemstone testers are invaluable tools for both jewelers and enthusiasts to quickly verify the authenticity of stones. Depending on what you are looking to measure, there are two main types of testers on the market.
Here is a quick guide to the most common digital testers:
Thermal Conduction Testers
- These are the industry standard for distinguishing real diamonds from common imitations such as glass and cubic zirconia (CZ).
- How they work: Diamonds conduct heat extremely well. The tester has a small metal tip that you press against the stone. If it is a real diamond, the heat is immediately dissipated, giving a reading on a meter.
- Pros: They are very accurate at detecting glass and other cheap imitations, and they are often very easy and quick to use.
- Cons: Most traditional thermal conductivity testers cannot distinguish a real diamond from synthetic moissanite, as moissanite has a similar thermal conductivity.
Conductivity Testers (Moissanite Testers)
- These are often used as a complement to the diamond tester.
- How they work: These measure the electrical conductivity of the stone. Moissanite conducts electricity very well, while a natural diamond (with the exception of some rare types) does not.
- Advantages: The absolute safest way to determine whether the stone is a diamond or a synthetic moissanite.
Combined testers (2-in-1 Testers)
- These are very popular for hobbyists and professionals who want everything in one.
- How they work: The device has two separate sensors that measure both heat and electrical conductivity. This way, it can rule out both glass, cubic zirconia and moissanite.
- Advantages: All-in-one solution. You get fast answers and don't have to buy two separate devices.
Refractometers and Spectrometers (Digital for Colored Gemstones)
- If you want to test sapphires, rubies, emeralds or other colored stones, regular diamond testers are not enough.
- How they work: These measure the stone's refractive index (how light bends as it passes through the stone) or its light absorption spectrum. This provides a specific "fingerprint profile" of what type of mineral the stone is.
- Advantages: Can identify exactly what gemstone it is and reveal whether it is natural or synthetically produced.
- Disadvantages: Requires more knowledge from the user (you have to interpret the readings) and are significantly more expensive.
