Materials
Mineral
Citation Formats
General Reference
APA Style
BibTeX
A crystalline form of aluminium oxide and a rock-forming mineral, naturally transparent but colored by transition metal impurities. Its two primary gem varieties are ruby, red from chromium, and sapphire, whose colors depend on which transition metal is present. Pure corundum is defined to have 9.0 on the Mohs scale and can scratch almost all other minerals.
Facts
Formation ClassOxide mineral (aluminium oxide), forming in aluminum-rich, silica-poor igneous and metamorphic rocks; its gem varieties, ruby and sapphire, crystallize in these same settings. 1 Chemical Formula Hardness (Mohs) Cross-Tradition Connections
Associated With
Pure corundum is defined to have 9.0 on the Mohs scale.
In Discipline
Sources
1. Corundum (Wikipedia)
Wikimedia FoundationLead sectionQuote, Lead section
Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost all other minerals.
Reader Challenges (0 open reader challenges)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.
View At A Past Year
The atlas records no dated fact of its own for this entry, so there is no other year to choose.