Corundum
At a glance
- Type
- Mineral
- Group
- Oxide
- Crystal system
- Trigonal
- Hardness
- Very hard (over 7.5)
- Colour
- Grey, Brown
- Lustre
- Glassy, Brilliant
- Use
- Gemstone, Industry
- Difficulty in WildGuessr
- Medium
Did you know?
- Ruby and sapphire are both corundum: red corundum is ruby, and every other colour is called sapphire.
- Rubies get their red from tiny amounts of chromium, and blue sapphires from iron and titanium.
Could you guess it from clues?
WildGuessr picks a secret animal, plant, fungus, stone, prehistoric creature or space object and you ask yes-or-no questions about it, such as its group or where it grows. The fewer clues you need, the more points you score.
Similar stones
Classification, names and conservation status come from Wikidata (CC0), the photo from Wikimedia Commons. Wikidata Q131777 · All stones · All entries