Mineral 1.0Test your knowledge of specific minerals

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HornblendeCa2(Mg,Fe)4Al(Si7Al)O22(OH,F)2

Class: Silicate
Subclass: Amphibole
Hardness: 5 - 6
Density: 3.3 - 3.4
Streak: White or gray
Lustre: Vitreous
Habit: Intergrown crystals, prismatic character of grains.
Colours: Black

  Crystal System: Monoclinic
Cleavage: 2 at 56 and 124
Fracture: Uneven / conchoidal
Magnetism: None
Reaction with HCl: None

Identification in hand sample:
Prominent striations, prismatic crystals and angle on cleavages is distinguishing.

Associations:
Forms in igneous rocks, and in the metamorphic rock amphibolite.

Industrial / ecomonic uses:
Ornamental.

  

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