ARCGems.com Gemology Blog

Saturday, March 04, 2006

Anatase and Brookite Crystal specimens

On my trip to Pakistan (January 2006), this winter, I saw very nice little specimens of Anatase and Brookite. For me these were quite exciting crystal specimens because they they are very rarely seen in the markets. These specimens were allegedly from Waziristan, Pakistan.

Looking at Anatase, at first sight I thought they were zircon crystals on a clay matrix because of their high lustre. The seller said that it was Anatase and later on I found out that he was not lying. Actually the crystals had basal pinacoid which zircon does not have.

Brookite was also new to me. It was reddish brown very thin crystal. It surely has a very nice look to it but I realised that it was breaking off from the matrix very easily.

Below are two pictures and some more info about the two gemstone crystal specimen.

The TiO2 group is composed of rutile, anatase, and brookite and their crystal system Tetragonal, Tetragonal and Orthogonal respectively.

Brookite Crystal Specimen

Brookite Formula: TiO2
System: Orthorhombic
Colour: Brown, Black, Red.
Lustre: Metallic
Hardness: 5½ - 6


Anatase Crystal Specimen

Anatase Formula: TiO2
System: Tetragonal
Colour: Brown, indigo blue, ...
Lustre: Adamantine,Resinous
Hardness: 5½ - 6

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