Vesuvianite
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Vesuvianite, also known as idocrase, is a green, brown, yellow, or blue silicate mineral. Vesuvianite occurs as tetragonal crystals in skarn deposits and limestones that have been subjected to contact metamorphism. It was first discovered within... Wikipedia
Cleavage: Poor on, and, very poor on
Crystal class: Ditetragonal dipyramidal (4/mmm); H-M symbol: (4/m 2/m 2/m)
Crystal habit: Short pyramidal to long prismatic crystals common, massive to columnar
Crystal system: Tetragonal
IMA symbol: Ves
Luster: Vitreous to resinous
Mohs scale hardness: 6–7