The “MLD” Moissanite Scam: New Acronym, Old Trick—Here’s How It Works

The “MLD” label has started appearing in online jewelry listings and social media posts. It looks official, but it’s often a deliberate attempt to blur the line between diamond and moissanite. This article explains how the “MLD” trick works, why it matters, and what practical steps you can take to avoid being misled. I’ll give clear tests, red flags, and exact questions to ask sellers.

What “MLD” usually means

“MLD” is not a recognized gemological term. In many listings it stands for phrases like “Moissanite Lab Diamond” or “Man-made Lab Diamond”, intentionally ambiguous. Sellers use the letters to make a non-diamond look like a lab-grown diamond. The goal is to get buyers to assume they’re buying a real diamond—natural or lab-grown—when they are not.

Why this is a problem

Moissanite is a legitimate gemstone made of silicon carbide (SiC). It’s attractive and affordable. But moissanite is not diamond. They have different chemical composition, optical properties, hardness, resale value, and maintenance needs. When a seller hides that difference, it’s fraud. You pay a price—and expect a specific commodity—but receive something else.

Key technical differences (so you know what to look for)

• Chemistry: Diamond = carbon (C). Moissanite = silicon carbide (SiC).
• Hardness: Diamond = 10 on Mohs. Moissanite ≈ 9.25. Moissanite resists scratches well but is softer than diamond.
• Refractive index (RI): Diamond ≈ 2.42. Moissanite ≈ 2.65–2.69. Higher RI means more brilliance but also different light behavior.
• Dispersion (“fire”): Diamond ≈ 0.044. Moissanite ≈ 0.104. Moissanite often shows stronger rainbow flashes—more colorful fire—because of higher dispersion.
• Optical behavior: Moissanite is birefringent. Under magnification some facet edges or facets appear doubled. Diamond is singly refractive and does not show facet doubling.

How sellers use “MLD” to confuse buyers

• They list “MLD 1.5ct” without using the word moissanite. Buyers see “ct” and assume carat weight for a diamond.
• They provide generic certificates showing size and weight but not an independent lab grade (GIA/AGS). The certificate may come from the vendor and not from a recognized lab.
• Photos are often highly retouched or stock images that hide the characteristic fire and facet doubling of moissanite.
• They may cite “lab-grown” to reassure buyers, then claim “MLD” is a lab process for diamonds—intentionally vague language.

Red flags when shopping

• Listing uses acronyms like “MLD,” “MLD diamond,” or “lab diamond” but never says “moissanite.”
• Price close to natural or lab-grown diamond prices. Moissanite should cost a fraction of a diamond of equivalent size and face-up appearance.
• No independent lab report (GIA, IGI, AGS) for a stone represented as a diamond. Sellers offering diamond prices should show diamond certificates.
• Seller refuses to confirm in writing that the stone is a diamond (natural or lab-grown) or refuses to name the material explicitly.
• High-resolution photos show unusually large or colorful fire; that can signal moissanite rather than diamond.

Simple tests you can do or request

• Ask for a lab report. If the seller claims “diamond,” ask for a GIA, AGS or IGI report. Those labs grade diamonds and will state if the stone is not a diamond.
• Request a clear photo through a jeweler’s loupe (10x). Moissanite can show facet doubling or a birefringent “doubling” effect on the pavilion facets; diamonds do not.
• Look for color of the flashes. Strong, rainbow-colored fire in a white light photo often points to moissanite because of its higher dispersion.
• Ask for an electrical conductivity test or a moissanite-specific tester result. Thermal testers can be fooled by moissanite; electrical testers can distinguish them.
• Take the stone to a reputable local jeweler and ask for an identification. A trusted jeweler with the right tools can tell moissanite from diamond quickly.

Price guidelines (ballpark)

Exact prices vary, but typical retail for a single round near-colorless lab-grown diamond around 1.0 ct commonly runs from roughly $1,200 to several thousand dollars depending on cut, color, and clarity. Moissanite of similar face-up size often sells for roughly $350–$1,000 retail, depending on brand and cut. If a “diamond-like” listing is priced in the moissanite range yet uses diamond-like language, question it.

What to ask sellers—exact phrases

• “Is the stone a natural diamond, a lab-grown diamond, moissanite (silicon carbide), or another material? Please answer yes/no and state the material.”
• “If you claim ‘diamond,’ please provide a GIA, AGS, or IGI report with the report number.”
• “If the stone is moissanite, please provide the maker certificate (brand) and confirm it is silicon carbide in writing.”

If you discover you were misled

• Request a refund immediately and cite the listing language and your evidence (photos, messages). Keep copies.
• If the seller refuses, open a dispute with your payment provider or credit card company. Card networks and PayPal often protect buyers for misrepresentation.
• Report the seller to your local consumer protection agency. Misrepresenting gemstones can be fraud under consumer laws.
• Ask a reputable jeweler to provide a written identification—this helps with disputes and possible legal claims.

Bottom line

“MLD” is an intentionally vague marketing label. It can mean moissanite or something else, and it’s often used to suggest a diamond without saying the word. Moissanite is a fine stone, but it should be sold honestly. Ask direct questions, insist on independent lab reports if you’re paying diamond prices, and get a hands-on test if anything seems off. Clear identification and written disclosure are the simplest ways to protect your purchase.