Jadeite
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Jadeite is a pyroxene mineral with composition NaAlSi₂O₆. It is hard, very tough, and dense, with a specific gravity of about 3.4. It is found in a wide range of colors, but is most often found in shades of green or white. Wikipedia
Density: 3.25 - 3.35
Birefringence: δ = 0.013 – 0.020
Category: Pyroxene group
Cleavage: Good on
Crystal class: Prismatic (2/m); (same H-M symbol)
Crystal system: Monoclinic
Fracture: Splintery