Reniform or
"kidney ore" Hematite
A
somewhat reniform mass of Hematite displaying a reddish color.
Specular (micaceous) Hematite from Michigan showing a bright metallic luster.
Hematite MMT315 from Hurley
Michigan. Montreal Mine
CHEMISTRY Fe2O3 Iron oxide
CRYSTALLOGRAPHY Hexagonal
CRYSTAL GROWTH AND HABITS Crystals of Hematite are commonly complex rhombohedrons or prisms. Hematite is also common as thin tabular to micaceous crystals and as radiating fibrous, stalactitic, massive earthy, granular and oolitic.
COLOR AND OTHER OPTICAL PROPERTIES Hematite is steel gray to dull gray and reddish. It is opaque.
HARDNESS 5.5 - 6.5
SPECIFIC GRAVITY 5.26
LUSTER Metallic to dull and earthy
STREAK Reddish brown
BREAKABILITY Uneven to subconchoidal fracture, brittle
OCCURRENCE Hematite is found as an accessory mineral in felsic igneous rocks and as crystals in high temperature hydrothermal veins. It is also found as a cement in sedimentary rocks or in massive oolitic deposits.
ASSOCIATED MINERALS Ilmenite, Rutile, Magnetite, Goethite