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corundum

File:Several_corundum_crystals.jpg · Wikimedia Commons · See Wikimedia Commons

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corundum

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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

via Wikipedia infobox

Wikidata facts

Has part
aluminium oxide
Named after
ruby
Image
Corundum.jpg
Show 10 more facts
streak color
white
Commons category
Corundum
topic's main category
Category:Corundum gemstones
Nickel-Strunz 9th edition (updated 2009)
4.CB.05
chemical formula
Al₂O₃
Nickel-Strunz '10th ed', review of (9th ed/ 2009 update)
4.CB.05
Mohs' hardness
9
crystal system
trigonal crystal system
IMA Mineral Symbol
Crn
Strunz 8th edition (series ID, updated)
IV/C.04a
Sources (3)

via Wikidata · CC0

~8 min read

Encyclopedic overview

6 sections
Contents
  • Geology and occurrence
  • Synthetic corundum
  • Structure and physical properties
  • Structure type
  • See also
  • References

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.

The name "corundum" is derived from the Tamil-Dravidian word kurundam (ruby-sapphire) (appearing in Sanskrit as kuruvinda).

Excerpted from Wikipedia’s “corundum” article, available under the CC BY-SA 4.0 licence.

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