Topaz Buying Guide: Natural vs Lab-Grown, Prices per Carat & Quality

What is topaz?

Topaz is an aluminium silicate; pure topaz is colourless. Hardness: 8 (but cleaves easily) on the Mohs scale.

Colour and quality factors

Golden-orange to pink 'Imperial' topaz is most valuable; natural pink is rare; London, Swiss and sky blue are almost always treated.

Origins and natural (mined) stones

Brazil (Ouro Preto for Imperial), Pakistan (pink), Sri Lanka, Nigeria and the US.

Carat weight and size

Large clean stones are common and inexpensive for blue; Imperial topaz rises steeply in size.

Prices per carat

Treated blue: roughly $5–$50/ct. Imperial: roughly $500–$3,000/ct. Natural pink: higher. These are indicative retail ranges per carat gathered from published trade and auction reporting; real prices vary widely with colour, size, origin and treatment, and are not a Riakoob quote.

Natural vs lab-grown (synthetic)

Synthetic topaz is rare on the market; treated topaz is far more common. Under US FTC guidelines a lab-made stone must be clearly described as laboratory-grown, laboratory-created or synthetic, never simply by the gem name.

Treatments you must know about

Blue topaz is irradiated and heated; 'Mystic' topaz is surface-coated and can wear. Treatment disclosure is required; ask for it in writing and on the lab report.

Certification

For significant topaz purchases, ask for a report from an independent lab such as GIA, AGL, SSEF or Gübelin stating natural or synthetic origin, any treatments and, where relevant, geographic origin.

Care and durability

Avoid hard knocks (cleavage) and ultrasonic cleaning for coated stones.

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