Original description: Lorenzen, J., 1884. Undersøgelse af Mineralier fra Grønland — Meddelelser om Grønland 7: 1—32 [
view in ‘Library’].
Type locality: Fiskenaes old harbour, Fiskenaes, Nuuk, Sermersooq, Greenland.
Type material: Københavns Universitet, Copenhagen, Denmark, 1883.754 (
Anthony et al., 2001—2005).
Etymology: in honour of Andreas Nikolaus Kornerup, Danish geologist.
Distribution: Germany: Waldheim, Saxony; Greenland; Madagascar; Norway; South Africa; Sri Lanka: gem gravels of the Ratnapura; Tanzania (
Anthony et al., 2001—2005).
Chemistry
Mg3Al6(Si,Al,B)5O21(OH)
Essential elements: hydrogen (H), boron (B), oxygen (O), magnesium (Mg), aluminium (Al), silicon (Si).
Crystal data
Crystallography: orthorhombic — dipyramidal.
Crystal habit: crystals prismatic, to over 20 cm, rarely terminated; as radiating aggregates (
Anthony et al., 2001—2005).
Optical properties
Colour: colourless, white, blue, green, dark green, greenish yellow, yellow-brown, black (
Anthony et al., 2001—2005).
Diaphaneity: transparent to opaque (
Anthony et al., 2001—2005).
Lustre: vitreous (
Arem, 1987: 120).
Refractive index: 1.660—1.685 — anisotropic [biaxial (-)] (
Lazzarelli, 2012).
Birefringence: 0.012—0.017.
Dispersion: 0.018 (
Arem, 1987: 120).
Pleochroism: X = colourless to green; Y = colourless, pale brownish yellow, pale yellowish green; Z = pale brownish green, green, light amber (
Anthony et al., 2001—2005).
Material from ‘Repository’
5 specimens: 0427 — 0.59 ct, Sri Lanka, North Central Province, Elahara;
0104 — 1.35 ct, Sri Lanka;
0436 — 0.66 ct, Sri Lanka;
0453 — 0.22 ct, Madagascar;
0644 — 0.44 ct, Sri Lanka.
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Gallery view
