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Kornerupine
Current inventory:  0 gems
 

Chemistry:  Mg₃Al₆(Si,Al,B)₅O₂₁(OH)

Discovered in 1884;   IMA status: Valid (pre-IMA; Grandfathered).
Kornerupine is named after the Danish geologist, Andreas Nikolaus Kornerup (1857-1883).

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/B.31-10

Nickel-Strunz 10th Ed. ID:

9.BJ.50

9 : SILICATES (Germanates)
B : Sorosilicates
J : Sorosilicates with Si₃O₁₀, Si₄O₁₁, etc. anions; cations in octahedral [6] and greater coordination

Related to:

n/a

Crystal Data

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

Crystals prismatic, to over 20 cm, rarely terminated; also as radiating aggregates and distinctly fibrous forms.

Twinning:

None

Physical Properties

Cleavage:

[110] Distinct

Fracture:

Uneven, Conchoidal

Tenacity:

Brittle

Hardness (Mohs):

7.0

Density:

3.28 - 3.35 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Colorless, White, Bluish Green, Green, dark Green, Greenish Yellow, Yellowish Brown, Black

Transparency:

Transparent to Translucent and Opaque

Luster:

Vitreous

Refractive Index:

1.660 - 1.684  Biaxial ( - ); may be pseudouniaxial ( - )

Birefringence:

0.0130 - 0.0140

Dispersion:

r > v or r < v;  0.018

Pleochroism:

Distinct; X = colorless to green; Y = colorless, pale brownish yellow, pale yellowish green; Z = pale brownish green, green, light amber

Occurances

Geological Setting:

In boron-rich volcanic and sedimentary rocks subjected to amphibolite to granulite facies metamorphism; in metamorphosed anorthosite complexes.

Common Associations:

Sapphirine, Cordierite, Spinel, Corundum, Tourmaline, Grandidierite, Dumortierite, Kyanite, Sillimanite, Andalusite, Biotite, Phlogopite, Magnetite, Ilmenite, Hematite, Rutile

Type Locality:

Fiskenaes old harbour, Fiskenaes (Fiskenaesset; Qeqertarsuatsiaat), Nuuk (Godthåb), Kitaa (West Greenland) Province, Greenland

Year Discovered:

1884

View mineral photos:

Kornerupine Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Kornerupine is a rare gemstone that is available in shades of green, bluish green, yellowish green and yellowish brown. The most desirable gems are the emerald green gems from Sri Lanka and Tanzania that are colored green by the presence of vanadium. Beautiful bluish green Kornerupine gems come from Madagascar and cats eye cabochons are available from Sri Lanka. Star Kornerupine has been found in Mogok, Myanmar (Burma) but is very rare. Kornerupine was originally found in Greenland as non-gemmy, radiating crystals but later found there as dark green cuttable crystals.

Current sources of gem quality crystals are Gatineau County, Quebec, Canada; Kwale district, Kenya; Itrongahy, Madagascar; Mogok, Myanmar (Burma); the gem gravels of Sri Lanka; Tanzania.
 

  
Kornerupine gems for sale:

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