Topaz
| Colour | Blue, Yellow, Clear, White, Brown, Orange, Gray, Green, Pink, Red |
|---|---|
| Mohs hardness | 8 (defining mineral) |
| Lustre | Vitreous |
| Streak | Grayish White |
| Crystal system | Orthorhombic |
| Transparency | Transparent |
| Cleavage | [001] Perfect |
| Fracture | Subconchoidal to uneven |
| Specific gravity | 3.49–3.57 |
What is Topaz?
Topaz is a silicate mineral made of aluminum and fluorine with the chemical formula Al2SiO4(F, OH)2. It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden-brown to yellow-orange. Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple.
How to identify Topaz
- Lustre: Vitreous.
- Hardness: Mohs 8 (defining mineral) — hard enough to scratch glass.
- Streak: Grayish White.
- Habit: Orthorhombic crystal system.
Topaz value
Topaz is a fine gemstone priced per carat by quality — colour, clarity, cut, carat and origin — not by weight in grams. Typical market ranges:
| Quality | Price per carat |
|---|---|
| Commercial | $5–$25 / ct |
| Good | $25–$200 / ct |
| Fine | $100–$1,500 / ct |
| Top | $1,000–$3,500 / ct |
Ranges cross-validated across two independent research passes against gemstone price guides, 2026-06 — sources: palagems.com, rubyglint.com. Colour saturation, clarity, cut and origin move the price enormously, and treatments or lab-grown stones sell for a fraction — so this is a guide, not an appraisal. Have anything valuable checked by a certified gemmologist. See the full crystal & gemstone value guide.
