Kornerupine

Physical & Optical Properties

Mohs Hardness 6,5
Specific Gravity 3,25 – 3,45
Refractive Index 1,66 – 1,685
Crystal System Orthorhombic
Luster Vitreous
Cleavage Good
Fracture Conchoidal
Color various
Birefringence 0,012
Dispersion 0,018
Pleochroism Strong trichroism is common for green variety: green - yellow - reddish brown

Mohs Hardness

1 Talc 2 Gypsum 3 Calcite 4 Fluorite 5 Apatite 6 Orthoclase 7 Quartz 8 Topaz 9 Corundum 10 Diamond Kornerupine
Mohs hardness of Kornerupine shown against the ten reference minerals, from talc (1) to diamond (10).
Mohs Reference mineral Kornerupine
1 Talc
2 Gypsum
3 Calcite
4 Fluorite
5 Apatite
6 Orthoclase
7 Quartz
8 Topaz
9 Corundum
10 Diamond

Crystal System

a b c Orthorhombic a ≠ b ≠ c, α = β = γ = 90°

Value & Market

Price Tier Moderate ($50-500/ct)

About Kornerupine

Kornerupine is a rare magnesium iron aluminum borosilicate mineral occurring in green, brown, yellow, and colorless transparent prismatic crystals with strong trichroism displaying yellow-brown, green, and sometimes red tones. It was first described in 1884 from Greenland and named after Danish geologist Andreas N. Kornerup, with gem-quality material sourced from Sri Lanka, Madagascar, Tanzania, Myanmar, and Canada. The finest green and cat's-eye varieties are prized by collectors and connoisseurs for their rarity and pleochroic color change.

Science FYI Family

Frequently Asked Questions

What is Kornerupine?
Kornerupine is a rare magnesium iron aluminum borosilicate mineral occurring in green, brown, yellow, and colorless transparent prismatic crystals with strong trichroism displaying yellow-brown, green, and sometimes red tones. It was first described in 1884 from Greenland and named after Danish geol
What is the hardness of Kornerupine?
Kornerupine has a Mohs hardness of 6.5, making it moderate for use in jewelry.
What color is Kornerupine?
Kornerupine is primarily Various.
How much does Kornerupine cost?
Kornerupine falls into the Moderate ($50-500/ct) price range. Prices vary based on color, clarity, cut, and origin.
What is the crystal system of Kornerupine?
Kornerupine belongs to the Orthorhombic crystal system.

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