Hematite ↗
Mineral species
Hematite can be earthy red, sparkling and platy, or dark with a metallic sheen. These very different appearances are a useful reminder that one mineral can take many forms.
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Crystal Guide / All families
Chemical reading shelf, not one species
Iron oxides & oxyhydroxides.
Hematite, magnetite and goethite have different compositions. Limonite is a variable mixture/field term; this shelf does not merge them scientifically.
Keep each chapter’s scientific identity: a family, species, variety, trade label, rock and fossil are different kinds of names.
Magnetite ↗
Mineral species
Magnetite is a dark iron oxide with a genuine measurable magnetic property. Its black surfaces and sometimes crisp crystal forms make it interesting without adding claims about the body.
Robert M. Lavinsky · CC BY-SA 3.0 · Display cropGoethite ↗
Mineral species
Goethite can be brown, black, earthy, fibrous or subtly reflective. It is a useful reminder that iron-bearing minerals need not have the same appearance as polished metallic hematite.
Robert M. Lavinsky · CC BY-SA 3.0 · Display cropLimonite ↗
Mixture / field term
Limonite is a field term for variable iron-rich weathering material, rather than one distinct mineral species. Its earthy brown appearance can cover several mineral mixtures.
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