HEMATITE
Hematite is a common iron oxide mineral (Fe2O3).
It varies in appearance, for example from nonmetallic-lustered and brick red-colored
to metallic-lustered and silvery-gray colored.
Brick red hematite is often powdery or finely granular or oolitic.
Silvery-gray hematite (micaceous hematite) is less common and results from mild
to moderate levels of metamorphism. Hematite ranges in hardness from soft
to moderately hard (about 1 to 6 on the Mohs Hardness Scale). Regardless
of a specimen’s color or luster, hematite will always leave a brick red-colored
streak, which is its most diagnostic physical property.
Oolitic hematite (3.7 cm across)
Specular hematite (micaceous hematite) (4.3 cm across)
Reniform hematite ("kidney ore") from Cleator Moor Iron
Mines, Cumbria, England (CMC RM 1290, Cincinnati Museum Center's rock &
mineral collection, Cincinnati, Ohio, USA).