Does Moissanite Pass a Diamond Tester? How to Tell the Difference

Yes, moissanite can pass some traditional diamond testers. This happens because moissanite conducts heat efficiently, which can cause a basic thermal diamond tester to identify it as a diamond. However, specialized testers that measure both thermal and electrical properties can often distinguish moissanite from diamond.

If you are buying an engagement ring, checking a gemstone, or simply curious about moissanite, understanding how diamond testers work can help you identify the difference.

In this guide, we explain why moissanite can pass a diamond tester, how different testing methods work, and how to distinguish moissanite from natural and lab-grown diamonds.

Can Moissanite Pass a Diamond Tester?

Yes, moissanite can sometimes pass a traditional thermal diamond tester.

A basic thermal diamond tester measures how quickly heat travels through a gemstone. Diamond has exceptionally high thermal conductivity, and moissanite also conducts heat efficiently.

Because their thermal properties overlap, some traditional testers may produce a positive diamond reading when testing moissanite.

However, a positive reading does not automatically mean that the gemstone is a real diamond.

Moissanite is a separate gemstone made from silicon carbide (SiC), whereas natural and lab-grown diamonds are made from carbon.

The important difference: A basic thermal tester may confuse moissanite with diamond, but a suitable multi-tester can provide additional information to help distinguish them.

Why Does Moissanite Pass a Diamond Tester?

The main reason is its thermal conductivity.

Diamond is one of the best natural thermal conductors. Moissanite also has high thermal conductivity, which makes it difficult for some basic testing devices to distinguish between the two gemstones using heat alone.

Here is how they differ:

• Diamond: A naturally occurring or laboratory-grown carbon gemstone with exceptionally high thermal conductivity.

• Moissanite: A silicon carbide gemstone with high thermal conductivity and distinctive optical properties.

• Testing result: Some traditional thermal testers may identify both gemstones as diamond.

The reading can depend on the tester's technology, calibration, temperature, contact with the gemstone, and testing conditions.

Moissanite does not become a diamond simply because it produces a positive reading on a diamond tester.

Can an Electrical Diamond Tester Detect Moissanite?

Yes, an appropriate electrical conductivity tester can help distinguish moissanite from diamond.

Unlike a traditional thermal tester, an electrical tester measures how a gemstone responds to an electrical current.

Many modern dual diamond testers combine thermal and electrical measurements to help identify moissanite more accurately.

However, these devices also have limitations. Certain diamonds, including some boron-containing blue diamonds, can conduct electricity. Testing results can also vary depending on the gemstone and the instrument.

For this reason, a handheld tester should not be considered absolute proof of gemstone identity.

Thermal Diamond Tester vs. Dual Diamond Tester

Understanding the difference between these two devices is important when testing moissanite.

Which is better?

A dual tester is generally more useful when checking whether a gemstone is moissanite or diamond. However, for valuable jewelry or uncertain results, professional gemological identification is recommended.

Moissanite vs. Diamond: What Is the Difference?

Moissanite and diamond can look similar, especially when viewed without magnification. However, they have different chemical compositions, optical properties, and physical characteristics.

Both gemstones are durable and suitable for many jewelry designs.

Moissanite is particularly popular among buyers who enjoy vibrant rainbow flashes, while diamond is preferred by people who want its traditional optical appearance.

To understand the differences in greater detail, read our guide to moissanite vs. diamond.

How Can You Tell Moissanite from a Real Diamond?

A single diamond tester reading is not always enough to identify a gemstone correctly.

Here are four methods that can help.

1. Use a Dual Diamond Tester

A suitable dual tester measures both thermal and electrical conductivity.

It can help distinguish moissanite from diamond, although results depend on the instrument and gemstone characteristics.

Always follow the manufacturer's instructions and ensure the device is properly calibrated.

2. Examine the Gemstone Under Magnification

A trained jeweler can examine a gemstone using a 10x loupe or a gemological microscope.

Moissanite is doubly refractive, meaning light can split into two rays as it passes through the gemstone. Under suitable viewing conditions, this may produce a doubling effect in certain internal facet reflections.

Diamond is singly refractive.

This optical difference can help identify moissanite, although the result depends on the stone's cut, viewing direction, and examination conditions.

3. Examine Its Optical Properties

Moissanite generally produces stronger rainbow-colored flashes than diamond because of its higher dispersion.

However, sparkle alone cannot confirm gemstone identity. Cut quality, lighting, stone size, and viewing angle all affect appearance.

4. Request Professional Gemstone Identification

If you are unsure whether a gemstone is moissanite, natural diamond, or lab-grown diamond, consult a qualified gemologist.

Professional identification may involve specialized optical instruments and advanced testing equipment.

For valuable purchases, an independent gemological report can provide additional confidence.

Can a Diamond Tester Distinguish Lab-Grown Diamonds from Natural Diamonds?

No. A conventional handheld diamond tester generally cannot determine whether a diamond is natural or lab-grown.

Both natural and laboratory-grown diamonds are made of carbon and have essentially the same crystal structure and fundamental physical properties.

This means that conventional diamond testers generally identify both as diamonds.

Specialized gemological equipment is needed to determine whether a diamond was formed naturally or grown in a laboratory.

Here is a simple comparison:

• Natural diamond: Formed naturally beneath the Earth's surface over geological time.

• Lab-grown diamond: Created in a controlled laboratory environment using advanced growth technology.

• Moissanite: A different gemstone made primarily of silicon carbide.

Lab-grown diamonds are real diamonds, while moissanite is a separate diamond alternative.

Learn more in our guide to what is a lab-grown diamond.

Can a Jeweler Mistake Moissanite for a Diamond?

Yes, it is possible, especially when someone relies only on a basic thermal diamond tester or visual inspection.

Moissanite can closely resemble diamond, and its thermal conductivity can produce confusing readings on some testing devices.

However, experienced jewelers use multiple identification methods rather than depending on one test.

They may examine optical properties, internal characteristics, and the gemstone's response to specialized testing equipment.

If you are purchasing a valuable gemstone, ask the seller to clearly disclose its identity and provide appropriate documentation.

FAQ

Does moissanite pass a basic diamond tester?

Yes, moissanite can pass some traditional thermal diamond testers because it conducts heat efficiently. The result depends on the testing device and conditions.

Can moissanite fool an electronic diamond tester?

Some basic electronic testers may produce a diamond reading for moissanite. A suitable dual tester can help distinguish the two using additional electrical measurements.

Does moissanite pass a professional diamond tester?

It depends on the tester. Professional multi-testers are designed to identify moissanite more accurately than basic thermal testers, but no handheld device is completely foolproof.

Can lab-grown diamonds pass a diamond tester?

Yes. Lab-grown diamonds are real diamonds made of carbon. They generally produce diamond readings on conventional thermal and electrical diamond testers.

Is moissanite a fake diamond?

No. Moissanite is a genuine gemstone made of silicon carbide. It is not a diamond, but it is a popular alternative because of its brilliance, durability, and appearance.

Can you identify moissanite without a diamond tester?

A trained gemologist can use magnification and optical examination to help identify moissanite. However, visual inspection alone is not always conclusive.

Does moissanite lose its sparkle over time?

Moissanite does not normally lose its inherent brilliance with regular wear. However, dirt, oil, and residue can make it appear less sparkly. Gentle cleaning can help restore its appearance.

Which is better for an engagement ring: moissanite or diamond?

Both can be excellent choices. Moissanite offers a distinctive sparkle and a lower purchase price, while natural and lab-grown diamonds offer the properties and identity of a real diamond. Your choice depends on your budget, preferred appearance, and personal priorities.

Final Thoughts

Moissanite can sometimes pass a basic thermal diamond tester because of its high thermal conductivity. A dual tester can provide more information and help distinguish moissanite from diamond, but a handheld device should never be treated as definitive proof.

Remember three important points:

• Moissanite is a genuine gemstone, not a diamond.

• Natural and lab-grown diamonds are both real diamonds.

• Professional gemological identification is the best option when a gemstone's identity is uncertain.

At JBR Jeweler, we believe that understanding gemstone characteristics helps customers make confident jewelry decisions. Whether you prefer moissanite, natural diamonds, or lab-grown diamonds, knowing what you are purchasing is always important.