Dunilite
Dunilite is a rare olivine group mineral with the corresponding chemical formula Magnesium, Iron, Manganese, Silicate (Mg,Fe,Mn)2SiO4. Long mistaken for green peridot , dunilite was identified in 2000 as a new gem variety from the olivine group. Dunilite- Discovered by Mr. Dunil Palitha Gunasekera in 1996. Dunil Palitha Gunasekera Dip. Gem, FGA,- President Crystals Gallery -Gem Lab Dunilite occurs in only one locality called, “Katukubura mountain” Kolonne , Sri Lanka. Dunilite can be found in colours light greenish-yellow to brownish green, the depth of colour being related to the iron content of the stone. • Group : Olivine • Crystal System : Orthorhombic • Lustre : Vitreous • Fluorescence : None • Hardness : 6 1/2 • Fracture : Uneven • Cleavage : None • Specific Gravity : 3.48 • Optic Sign : Biaxial (-) • Dispersion : 0.020 • Transparency : Transparent to translucent • Habit : Tabular, rectangle shaped aggregate crystals. • Refractive Index : a= 1.677, B=1.