Topaz
Topaz is an aluminum silicate mineral prized for its hardness and brilliant colors. Imperial topaz (orange-pink) from Brazil is most valuable.
Topaz properties at a glance
| Type | Semi-Precious Stones |
|---|---|
| Chemical formula | Al2SiO4(F,OH)2 |
| Mohs hardness | 8 |
| Crystal system | orthorhombic |
| Luster | vitreous |
| Streak | White |
| Cleavage | Perfect basal |
| Fracture | Conchoidal |
| Specific gravity | 3.5 |
| Transparency | transparent |
| Common colors | Colorless, Blue, Yellow, Orange, Pink |
| Rarity | uncommon |
Geology & background
Forms in cavities of igneous rocks, particularly granite and rhyolite pegmatites, from fluorine-bearing vapors.
The Greeks believed topaz could make its wearer invisible; Romans associated it with Jupiter.
How to identify Topaz
- Check whether the specimen's color and texture match typical Topaz examples.
- Photograph a fresh surface in natural light and avoid shadows, glare, or wet surfaces.
- Use hardness, streak, luster, grain size, and locality together; no single trait is enough for every specimen.
Where Topaz is found
Topaz is reported from multiple localities or geological settings. Exact locality should be verified from specimen provenance, maps, or field notes.
How much is Topaz worth?
| Entry-level specimen | $20 |
|---|---|
| Typical collector specimen | $100 |
| Premium specimen | $3000+ |
Value depends on size, condition, color, crystal quality, locality, rarity, preparation, and provenance. Treat this as educational guidance, not an appraisal.
Common uses
- Jewelry
- Collector specimens
Interesting facts
- The largest cut topaz is the 'El-Dorado Topaz' at 31,000 carats
- Most blue topaz is colorless topaz that's been irradiated
- Ancient Greeks believed it gave them strength
Care & safety
Treat Topaz as a collector specimen unless hardness, cleavage, and fracture are confirmed.
Avoid inhaling dust. Do not cut, grind, or polish unknown specimens without eye protection and a properly rated respirator.
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