4.77 Ct Certified Loose Natural Oval Cut Yellow Green Kornerupine Ceylon-12750

4.77 Ct Certified Loose Natural Oval Cut Yellow Green Kornerupine Ceylon-12750

  • Product Code : Product 86
  • Availability : In Stock
  • $190.00

  • Ex Tax :$190.00

100% Natural - Not treated in any way.

Rare Collectors Gem !

Suitable for Museums,Institutions and Students of Gemology.

Will make a Gorgeous Ring or Pendent accented with Diamonds.

Gem with High Luster and Good Clarity.

A Gem of Lasting Beauty.

Refractive Index: 1.665 – 1.683 

Hardness: 6.50 

Chemical Comp: Mg4 (Al, Fe)6(Si, Al, B)5O21(OH), 

Density: 3.25 - 3.35 

Crystal Group: Orthorhombic 

Kornerupine is a rare gem; Sri Lanka is the main source country. This gem is pleochroic and comes in Green brown and yellow green.Kornerupine is a rare boro-silicate mineral with the formula (Mg,Fe2+)4(Al,Fe3+)6(SiO4,BO4)5(O,OH)2. It crystallizes in the orthorhombic - dipyramidal crystal system as brown, green, yellow to colorless slender tourmaline like prisms or in massive fibrous forms. It has a Mohs hardness of 7 and a specific gravity of 3.3 to 3.34. Its indices of refraction are na=1.660 - 1.671, nß=1.673 - 1.683 and n?=1.674 - 1.684. It occurs in boron-rich volcanic and sedimentary rocks which have undergone high grade metamorphism. It is also found in metamorphosed anorthosite complexes.[1] Kornerupine is valued as a gemstone when it is found in translucent green to yellow shades. The emerald green varieties are especially sought after. It was first described in 1884 for an occurrence in Fiskernaes in SW Greenland. It was named in honor of the Danish geologist, Andreas Nikolaus Kornerup (1857–1883).[2]

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