Hematite

Physical Properties
Chemical formula Fe2O3
Class Oxide
Crystal system Hexagonal (rhombohedral)
Habit Aggregate
Massive
Rosette
Botryoidal
Reniform
Micaceous/foliated
Tabular
Color Red-brown to black
Steel grey
Hardness 5.5 to 6.5
Specific gravity 4.9 to 5.3
Cleavage None
Fracture Subconchoidal
Luster Submetallic
Transparency Translucent to opaque
Streak Brick red
Optical Properties
PPL Usually opaque
If thin enough, may be deep red
XPL Usually opaque
If thin enough, may be deep red
δ 0.28
after Perkins, 371

Hematite in Hand Sample

Hematite

Oolitic hematite

Specular hematite

Purplish-blackish botryoidal hematite with whitish, radiating barite and reddish quartz on quartzite

Hematite in Thin Section

Hematite can be tricky. If it’s too thick, it’ll be as opaque as any metallic mineral. If it’s thin enough, you can see its reddish color in both PPL and XPL.

Thin Section GigaPans

Hematite cement in conglomerate, plane polars

Hematite cement in conglomerate, crossed polars

Hematite, PPL

Hematite, XPL

Conglomerate with hematite cement, plane polars
Conglomerate with hematite cement, plane polars

Conglomerate with hematite cement, crossed polars
Conglomerate with hematite cement, crossed polars

Further Reading

Hematite at webmineral.com

Hematite at mindat.org