Manganese dioxide and the most important ore of manganese. Forms dark metallic masses and dendritic surface stains. Color: Black, steel-gray. Luster: Metallic to dull. Streak: Black to bluish-black. Cleavage: Perfect in two directions. Hardness: 6-6.5 crystals , 2 massive. Transparency: Opaque. Crystal system: Tetragonal. Chemical formula: MnO₂. Specific gravity: 4.73-5.08. Formation: Forms by weathering and oxidation of manganese-bearing minerals and by precipitation from manganese-rich waters. Common geological settings: South Africa, India, Brazil, Ghana; forms the distinctive dendrite patterns on rock surfaces. Common look-alikes and related entries: Manganite, Hematite, Magnetite.
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These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
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Last updated
2026-03-30T14:37:43.029468+00:00
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IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
Manganese dioxide and the most important ore of manganese. Forms dark metallic masses and dendritic surface stains.
How can you identify Pyrolusite?
Compare several properties rather than relying on colour alone. This entry records colour: Black, steel-gray; lustre: Metallic to dull; streak: Black to bluish-black; Mohs hardness: 6-6.5 crystals , 2 massive; cleavage: Perfect in two directions; crystal system: Tetragonal; transparency: Opaque. Confirm an important identification with additional field tests or qualified laboratory work.
How does Pyrolusite form?
Forms by weathering and oxidation of manganese-bearing minerals and by precipitation from manganese-rich waters.
Where is Pyrolusite commonly found?
South Africa, India, Brazil, Ghana; forms the distinctive dendrite patterns on rock surfaces.
What is Pyrolusite commonly confused with?
Pyrolusite may be confused with Manganite, Hematite, Magnetite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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