Autunite identification and geology

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• Previous: Augite — The most common pyroxene mineral, forming dark stubby prismatic crystals with near-90° cleavage intersection.
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• Torbernite
• Sulfur

Sources, scope & corrections

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.

Editorial owner

GeoMiner

Last updated

2026-03-30T14:37:50.930611+00:00

Review status

Published; not independently peer-reviewed

• 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.
• Technologically Enhanced Naturally Occurring Radioactive Materials from Uranium Mining — U.S. Environmental Protection Agency. Official radiation-safety guidance for mineral collectors, including uranium- and thorium-bearing specimens.

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Common questions

What is Autunite?

Hydrated calcium uranyl phosphate with vivid yellow-green color and strong fluorescence. Important uranium prospecting mineral.

How can you identify Autunite?

Compare several properties rather than relying on colour alone. This entry records colour: Vivid yellow-green; lustre: Vitreous to pearly; streak: Yellow; Mohs hardness: 2-2.5; cleavage: Perfect basal; crystal system: Tetragonal; transparency: Transparent to translucent. Confirm an important identification with additional field tests or qualified laboratory work.

How does Autunite form?

Forms in the oxidized zone of uranium-bearing deposits and pegmatites by weathering of uraninite.

Where is Autunite commonly found?

France Autun , Portugal, USA, Australia; found in oxidized uranium deposits.

Is Autunite safe to handle?

Minimize handling and time near this specimen. Keep it in a closed, clearly labelled container away from occupied areas; do not cut, grind, powder, streak, or carry it in a pocket. Seek local radiation-safety guidance for large specimens or collections. Avoid creating dust or using destructive tests on an unknown specimen, and follow site-specific safety procedures.

What is Autunite commonly confused with?

Autunite may be confused with Torbernite, Uranophane, Sulfur. Compare multiple diagnostic properties because colour and surface appearance can overlap.