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Dunilite  (variety of Olivine)
Current inventory:  1 gem
 

Chemistry:  (Mg,Fe,Mn)₂SiO₄

Discovered in 1996;   IMA status: Not Valid (tradename)
Dunilite is named after its discoverer, Dunil Paligha Gunasekara (1947 - ), F.G.A., a gemologist from Sri Lanka.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/A.04-X

8 : Silicates
A : Nesosilicates, with [SiO4]4- groups, cations of tetrahedric orientation [4]
04 : Olivine group

Crystal Data

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

Crystals are tabular, flattened, rectangle shape corners often modified by a six-sided rhomb shape crystal faces.

Physical Properties

Cleavage:

[001] Good, [010] Distinct

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

6.5

Density:

3.48 (g/cm³)

Radioactivity:

Not Radioactive

Optical Properties

Color:

Greenish Yellow

Transparency:

Transparent to Translucent

Luster:

Vitreous

Refractive Index:

1.677 - 1.718  Biaxial ( - )

Birefringence:

0.041

Dispersion:

Relatively Weak

Pleochroism:

Strong : Brownish Yellow/ Greenish Yellow

Occurances

Geological Setting:

In a huge pale greenish yellow calcite vein associated with hercynite, magnetite, iron oxides, ferroedenite hornblende crystals.

Type Locality:

Katukubura Mountain, Kolonne, Sri Lanka

Year Discovered:

1996

View mineral photos:

Dunilite Mineral Photos and Locations

More Information

Mindat.org (Olivine)
Webmineral.com (Olivine)
 

Dunilite is a rare member of the Olivine Group that includes Dunilite, Fayalite, Forsterite and Peridot (Olivine) although Peridot is not recognized as a separate mineral. Dunilite is a very rare and recently discovered variety of Olivine that was discovered in 1996 in gem gravels at Katukubura Mountain, Kolonne, Sri Lanka it was originally thought to be a color variation of Peridot, and later determined to be a new gem variety. In addition to the dichroic color differences with Peridot, the RI values of Dunilite are quite different from those of Peridot. The GIA issued their report on Dunilite in 1998.
 

  
Dunilite gems for sale: