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Black Amethyst

The close-up view of each stone type shows a relatively true image of the crystalline structure and the colouring. This is suitable for grained slabs to a limited extend only. In regard to the colour matching, please take an original sample of the stone from your furniture store as a basis.

Petrography

In the case of this particular gabbro, revealed only recently, the rock is a medium-grained, full-crystalline, irregular stone consisting entirely of black pyroxenes (metal -bearing silicate minerals) and of bronzite crystals of up to 1cm in size, uniformly distributed throughout the rock. Exceptionally, there may be a magnetite ore present. Bronzite is a silicate mineral with a bronze-hued shimmer which is encountered especially in gabbroid rock. 

Petrogenesis

Star Galaxy is a magmatite rock which is described as pyroxenite because of its mineralogical make up. A silicate-rich magma solidified beneath the primeval earth crust under highly stable cooling conditions. The result was the homogeneous graining of this recently discovered stone.

Hardness Hard Stone
Structure Type Homogeneous Structure
Synonyms Nero Ametista, Black and Gold, Star Galaxy, Black Galaxy, Nero Galaxy
Group Plutonic rocks - Plutonite
Petrographic Assignment Gabbro
Age 1.4 billion years (Precambrian)
Colouring Minerals black pyroxene, bronze-colour broncite crystals
Average Hardness 7 (according to Mohs's hardness scale 1-10) / Natural stone
Deposit India - in the south-east Indian province of Andhra Pradesh in the vicinity of the village of Ongole