Ultimate Guide To Accurately Testing Vvs Moissanite Diamonds For Authenticity At Home

Moissanite has emerged as one of the most popular diamond alternatives, prized for its brilliance, durability, and ethical sourcing. When labeled as VVS (Very, Very Slightly Included), it suggests exceptional clarity—nearly flawless to the naked eye. However, with rising demand comes an increase in misrepresentation and counterfeit stones. While professional gemological labs offer definitive verification, you don’t always need to visit one to gain confidence in your stone’s authenticity. With careful observation and a few simple tools, you can conduct reliable at-home tests that help distinguish genuine VVS moissanite from fakes or lower-quality imitations.

Understanding Moissanite and VVS Clarity

Moissanite is a lab-created silicon carbide gemstone first discovered in meteorites by Dr. Henri Moissan in 1893. Today, nearly all moissanite on the market is synthetically produced under controlled conditions. Unlike natural diamonds, which are made of carbon, moissanite’s chemical composition gives it unique optical and physical properties—most notably higher refractive index and double refraction.

The term “VVS” refers to clarity grading. In both diamonds and moissanite, VVS means there are minute inclusions only visible under 10x magnification. For consumers, a VVS moissanite should appear clean and bright without visible flaws. However, because moissanite is typically more inclusion-free than even high-grade diamonds, some sellers misuse “VVS” as a marketing term rather than a standardized grade. True VVS moissanite will have negligible internal characteristics but may still show slight doubling when viewed through a loupe due to its birefringence.

“While moissanite isn't graded using the same system as diamonds, reputable vendors use 'VVS' to indicate stones with no visible inclusions under magnification.” — Dr. Lena Torres, Gemologist & Materials Scientist

Step-by-Step Guide: How to Test Moissanite at Home

Accurate identification starts with methodical testing. Each technique targets different properties of the gemstone. Conduct these steps in order for best results.

1. Visual Inspection Under Magnification: Use a 10x jeweler’s loupe or a digital microscope. Examine the stone for internal flaws. Genuine VVS moissanite may show tiny needle-like inclusions or growth patterns, but nothing obvious to the naked eye. Look for doubling of facet junctions—a telltale sign of double refraction unique to moissanite.
2. Refractometer Test (if available): Moissanite has a refractive index between 2.65–2.69, significantly higher than glass (1.5) or cubic zirconia (2.15–2.18). A calibrated refractometer can confirm this reading. Note: Most handheld models max out at 1.80, so specialized equipment is needed.
3. Thermal Conductivity Test: Use a diamond tester. Moissanite conducts heat similarly to diamond and will usually pass as “diamond” on older testers. However, newer dual-testers (measuring both thermal and electrical conductivity) can differentiate moissanite due to its higher electrical conductivity.
4. Double Refraction Check: Place the stone table-down over a fine line drawn on paper. If the line appears doubled when viewed through the crown, it’s likely moissanite. Diamonds do not exhibit birefringence.
5. UV Light Examination: Shine a long-wave UV light (365 nm) on the stone. Some moissanites emit a faint green, yellow, or gray fluorescence. Lack of reaction doesn’t rule it out, but strong blue glow may suggest cubic zirconia or synthetic sapphire.

Tip: Always clean the stone with mild soap and water before testing. Oils and residue can interfere with conductivity and visual clarity.

Do’s and Don’ts: Common Testing Mistakes

Action	Do	Don’t
Cleaning the Stone	Use warm water, mild dish soap, and a soft brush	Use harsh chemicals like bleach or acetone
Using a Diamond Tester	Use a modern dual-conductivity tester	Rely solely on older thermal-only testers
Magnification	Inspect under 10x magnification in good lighting	Assume clarity based on unaided vision alone
Storage During Testing	Keep in a soft cloth pouch away from other jewelry	Leave it on a hard surface where it can scratch or get lost

Real Example: Identifying a Misrepresented Stone

Sophia purchased what was advertised as a “VVS colorless moissanite engagement ring” from an online marketplace. The price seemed too good to be true—$299 for a 2-carat stone. At home, she used a 10x loupe and noticed no doubling effect. Curious, she borrowed a friend’s updated gem tester, which flagged the stone as non-conductive electrically—unusual for moissanite. Further UV testing revealed a bright blue glow. These inconsistencies led her to suspect cubic zirconia passed off as moissanite. She contacted the seller, returned the item, and later confirmed the stone was CZ through a local jeweler. Her diligence saved her from a costly mistake.

Essential Tools Checklist for Home Testing

• ✅ 10x jeweler’s loupe or digital USB microscope
• ✅ Dual-mode gem tester (thermal + electrical conductivity)
• ✅ UV flashlight (365 nm wavelength)
• ✅ White paper with a thin black line for double refraction test
• ✅ Mild cleaning solution and lint-free cloth
• ✅ Tweezers or stone holder (to avoid fingerprints during testing)

Tip: Store your testing tools in a dedicated case to prevent damage and ensure readiness for future evaluations.

Frequently Asked Questions

Can a diamond tester tell if a stone is moissanite?

Older diamond testers measure only thermal conductivity and often misidentify moissanite as diamond because both materials dissipate heat efficiently. Modern dual-testers detect electrical conductivity, which moissanite possesses and diamond lacks (except in rare types). Therefore, only advanced testers can reliably distinguish between them.

Is VVS a standard grade for moissanite?

No. The VVS classification originates from the GIA diamond grading scale. Moissanite isn’t officially graded using this system, but vendors use “VVS” informally to describe stones with no visible inclusions under 10x magnification. It’s more of a descriptive term than a certified grade.

Why does my moissanite look rainbow-colored?

Moissanite has a higher dispersion (fire) than diamond—0.104 vs. 0.044. This means it breaks light into spectral colors more intensely, creating noticeable rainbow flashes, especially in sunlight. This is normal and a key identifier of moissanite, not a flaw.

Final Tips for Ensuring Authenticity

Purchase from trusted vendors who provide third-party documentation or product specifications. Reputable brands like Charles & Colvard or Harrods-certified suppliers often include data sheets confirming cut, clarity, and origin. Avoid deals that seem too cheap—authentic VVS moissanite requires precise growing conditions and quality control, making ultra-low prices suspicious.

If possible, request a certificate of authenticity or lot number traceability. While not equivalent to a GIA report, these documents add transparency. Also, keep receipts and descriptions in case you need to dispute a claim later.

“The best defense against fraud is education. Knowing what to look for empowers buyers to make informed decisions.” — Marcus Reed, Certified Gemological Appraiser

Take Action Today

Testing your moissanite at home isn’t just about verifying value—it’s about ensuring trust in your purchase. Whether you’re evaluating a new acquisition or re-examining a family heirloom, applying these techniques brings clarity and confidence. Start building your at-home gemology toolkit, practice the double refraction test, and invest in a reliable dual-mode tester. Share your findings with others exploring ethical gemstones, and help promote transparency in the jewelry market.

💬 Have you tested your moissanite at home? What did you discover? Share your experience in the comments and help fellow readers spot authentic gems with confidence.