Diamond
| Colour | Clear, Yellow, Brown, Gray, Blue, Green, Black, White, Pink, Purple, Orange, Red |
|---|---|
| Mohs hardness | 10 (defining mineral) |
| Lustre | Adamantine |
| Streak | Colorless |
| Crystal system | Cubic |
| Transparency | Transparent to subtransparent to translucent |
| Cleavage | 111 (perfect in four directions) |
| Fracture | Irregular/Uneven |
| Chemical formula | C |
| Specific gravity | 3.52 |
What is Diamond?
Diamond is a mineral form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is a tasteless, odorless, strong, brittle solid, a poor conductor of electricity, colorless in pure form, and insoluble in water. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applic
How to identify Diamond
- Lustre: Adamantine.
- Hardness: Mohs 10 (defining mineral) — hard enough to scratch glass.
- Streak: Colorless.
- Habit: Cubic crystal system.
Diamond value
Diamond 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 | $1,500–$3,000 / ct |
| Good | $3,500–$6,000 / ct |
| Fine | $6,000–$15,000 / ct |
| Top | $10,000–$25,000 / ct |
Ranges cross-validated across two independent research passes against gemstone price guides, 2026-06 — sources: pricescope.com, thediamondprice.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.
