HORNBLENDE

Ca2(Mg, Fe, Al)5(Al, Si)8O22(OH)2
Calcium Magnesium Iron Aluminum Silicate Hydroxide

 Cleavage: imperfect in two directions at 56 and 124 degrees

 Colour: black to dark green

 Fracture: uneven

 Hardness: 5 - 6

 Luster: vitreous to dull

 Streak: brown to grey

 Possible Useage: mineral specimen

 More Info: Mineral Gallery, Mineralogy Database, Mineralogy Database