Prismatic columns of Hedenbergite
with a single attached crystal of Ilvaite. Specimen is from Owyhee County,
Idaho.
CHEMISTRY CaFeSi2O6 A member of the Pyroxene Group
CRYSTALLOGRAPHY Monoclinic
CRYSTAL GROWTH AND HABITS Forms prismatic crystals commonly in groups; granular and massive.
COLOR AND OTHER OPTICAL PROPERTIES Black, greenish black to brown; transparent to opaque.
HARDNESS 5.5 - 6.5
SPECIFIC GRAVITY 3.5 - 3.6
LUSTER Vitreous to dull
STREAK Grayish with a hint of dark green
BREAKABILITY Two good directions of cleavage; uneven fracture; brittle.
OCCURRENCE Hedenbergite forms as a product of metamorphism in rocks rich in iron. It is common in Fe-Mn skarns. It is also found in granites, syenites and even as xenoliths in kimberlite.
ASSOCIATED MINERALS Grunerite, Arfedsonite, Quartz, Fayalite
MINERAL NAME Named after the Swedish chemist M.A. Hedenberg who was the first to describe the mineral.