Corundum vs Diamond
| Property | Corundum | Diamond |
|---|---|---|
| 化学式 | Al2O3 | C |
| 晶系 | Trigonal | Cubic (Isometric) |
| 鉱物分類 | 04 Oxides and Hydroxides | 01 Native Elements |
| モース硬度 | 9.0 | 10.0 |
| 色 | Red (ruby), blue (sapphire), various colors | Colorless, yellow, brown, blue, green, pink |
| 光沢 | Adamantine | Adamantine |
| 条痕色 | Colorless | None |
| 透明度 | Transparent | Transparent |
| 劈開 | None | Perfect octahedral {111} |
| 断口 | Conchoidal to uneven | Conchoidal |
Key Differences
- ◆ Diamond (hardness 10) is harder than corundum (hardness 9) — the hardest natural mineral vs. the second hardest.
- ◆ Diamond is pure carbon; corundum is aluminum oxide (Al2O3).
- ◆ Diamond crystallises in the cubic system; corundum is trigonal.
- ◆ Both are used as abrasives, but diamond abrades corundum, not vice versa.
- ◆ Corundum gem varieties are ruby and sapphire; diamond gems are simply called diamonds.