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Round Cut~Natural~Kornerupine/Prismatine~0.5TCW~Balochistan, Pak~US Ship

$ 8.97

Availability: 100 in stock
  • All returns accepted: Returns Accepted
  • Total Carat Weight (TCW): 0.5TCW
  • Return shipping will be paid by: Buyer
  • Restocking Fee: No
  • Item must be returned within: 30 Days
  • Condition: New without tags
  • Color: Green
  • Refund will be given as: Money Back
  • Country of Origin: Pakistan
  • Shape: Round and Cushion
  • Natural/Lab-Created: Natural

    Description

    Round cut loose gemstone, 0.5TCW kornerupine/prismatine, green color
    Kornerupine (also called Prismatine) 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 orthohombic - 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 nα=1.660 - 1.671, nβ=1.673 - 1.683 and nγ=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.
    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 forms a solid solution series with prismatine. Strongly pleochroic, it appears green or reddish brown when viewed from different directions. It has a vitreous luster.