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Dunilite  (variety of Olivine)
Current inventory:  1 gem
 

Dunilite

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:

Dunilite-001

Gem:

Dunilite

Stock #:

DUNIL-001

Weight:

0.070 ct

Size:

2.46 x 2.22 x 1.48 mm

Shape:

Emerald

Color:

Olive Green

Clarity:

VSI

Origin:

Sri Lanka

Treatment:

None (natural)

Price:

SOLD (but we have others)

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Dunilite-001

A recently discovered (1996) rare gem from Sri Lanka. This gem is bright green and well cut.


 

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