How to Tell the Difference Between a Diamond and a Moissanite

When it comes to distinguishing between a diamond and a moissanite, the differences can be subtle, yet noticeable with the right tools and knowledge. Let's dive into the specifics of how you can effectively tell these two gemstones apart.

1. Brilliance and Sparkle

Diamonds and moissanites both exhibit remarkable brilliance, but their sparkle differs due to their distinct refractive indices. Moissanite has a higher refractive index (2.65-2.69) compared to diamonds (2.42). This means moissanites tend to exhibit more fiery brilliance and sparkle under light, often with a rainbow-like effect. A diamond, on the other hand, offers a more subdued sparkle that is typically less colorful.

2. Color

Diamonds are available in a wide range of colors, from completely colorless to shades of yellow and brown. The color grade is an essential factor in determining the quality and value of a diamond. Moissanites, however, are generally near-colorless or colorless, but they can show a slight yellow or grayish tint when compared to high-quality diamonds.

3. Hardness and Durability

On the Mohs scale of hardness, diamonds are rated at 10, making them the hardest known material. Moissanites, with a rating of 9.25, are also very hard but slightly less so than diamonds. This hardness makes diamonds more resistant to scratching and abrasion compared to moissanites. However, both gemstones are highly durable and suitable for everyday wear.

4. Heat and Thermal Conductivity

Diamonds and moissanites react differently to heat and thermal conductivity. Diamonds are excellent conductors of heat and will feel cold to the touch even in warm environments. Moissanites have lower thermal conductivity compared to diamonds, and using a thermal conductivity tester can help differentiate them.

5. Double Refraction

One of the most telling differences between diamonds and moissanites is double refraction. Moissanites exhibit a unique optical property called birefringence, meaning they can show doubled images of facets when viewed through certain angles. Diamonds, being singly refractive, do not exhibit this effect.

6. Price

Price can be a straightforward indicator. Moissanites are generally less expensive than diamonds due to their availability and the fact that they are lab-created. Diamonds, being natural gemstones, come with a higher price tag, particularly for high-quality, larger stones.

7. Certification and Testing

When in doubt, always seek certification. Reputable jeweler’s certificates or gemological lab reports provide detailed information about the gemstone, including its type, quality, and characteristics. Gemological testing with specialized equipment is also a reliable method to determine whether you are dealing with a diamond or a moissanite.

8. Visual Inspection

A careful visual inspection can reveal subtle differences. Moissanites often exhibit a more vibrant, rainbow-like sparkle due to their higher dispersion, while diamonds produce a more subdued, classic sparkle. Moissanites might also display a unique “flash” of colors that is not typical in diamonds.

9. Inclusion Patterns

Both diamonds and moissanites can have inclusions, but their patterns and types can differ. Diamonds may have natural inclusions or “blemishes” while moissanites, being lab-created, might have different internal characteristics. A jeweler with a loupe or microscope can help identify these differences.

10. Historical and Personal Significance

Understanding the history and personal significance of a gemstone can also be important. Diamonds have a long history of being a symbol of permanence and luxury, while moissanites, discovered by Henri Moissan and popularized more recently, offer a modern and ethical alternative to diamonds.

By carefully considering these aspects, you can effectively distinguish between a diamond and a moissanite. Whether you're purchasing a new piece of jewelry or evaluating an existing one, these tips will help ensure you make an informed decision.