corundum

Also known as corinvindum

Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium, and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. Corundum has two primary gem varieties: ruby and sapphire. Rubies are red due to the presence of chromium, and sapphires exhibit a range of colors depending on what transition metal is present. A rare type of sapphire, padparadscha sapphire, is pink-orange.

AI overview

Corundum is a hard, crystalline mineral made of aluminum oxide that naturally forms in rocks and can be transparent or colored depending on trace metals mixed within it. It's valued as a gemstone in two main forms—rubies (red) and sapphires (various colors)—making it one of the most prized materials in jewelry.

AI-generated from the Wikipedia summary — may contain errors.

Key facts

Mineral.name: Corundum
Mineral.category: Oxide mineral – Hematite group
Mineral.image: Several corundum crystals.jpg
Mineral.imagesize: 260px
Mineral.formula: Al2O3
Mineral.IMAsymbol: Crn
Mineral.strunz: 4.CB.05
Mineral.dana: 4.3.1.1
Mineral.system: Trigonal
Mineral.class: Hexagonal scalenohedral (m)H-M symbol: ( 2/m)
Mineral.symmetry: (No. 167)
Mineral.unit cell: , ;
Mineral.color: Colorless, gray, golden-brown, brown; purple, pink to red, orange, yellow, green, blue, violet; may be color zoned, asteriated mainly grey and brown
Mineral.habit: Steep bipyramidal, tabular, prismatic, rhombohedral crystals, massive or granular
Mineral.twinning: Polysynthetic twinning common
Mineral.cleavage: None – parting in 3 directions
Mineral.tenacity: Brittle
Mineral.fracture: Conchoidal to uneven