Anglesite
Lead sulfate (PbSO4)
A heavy lead sulfate secondary mineral, often colorless to white with adamantine luster, formed by the oxidation of galena.
- Mohs hardness
- 2.5-3
- Color
- Colorless, white, gray, pale yellow, green tints
- Type
- mineral
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Overview
Anglesite is lead sulfate (PbSO4), a secondary mineral that crystallizes in the orthorhombic system. It is typically colorless to white but can show gray, yellow, or green tints, and it has a high refractive index that gives well-formed crystals a brilliant adamantine to resinous luster.
Named after Anglesey, Wales, where it was first described, anglesite is notably dense because of its lead content, a useful diagnostic clue.
It is part of the barite group and forms directly from the oxidation of galena, often surrounding remnant cores of unaltered lead sulfide.
Formation & geology
Anglesite forms in the oxidized zones of lead ore deposits as a direct alteration product of galena (lead sulfide). When galena weathers in the presence of oxygenated, sulfate-rich water, it converts to lead sulfate.
Specimens frequently show concentric structure, with anglesite forming a rim or shell around a shrinking core of unaltered galena, recording the oxidation process.
Fine crystals come from Tsumeb (Namibia), Touissit (Morocco), Monteponi (Sardinia), Broken Hill (Australia), and the original Anglesey locality in Wales. It commonly associates with cerussite, galena, and other secondary lead minerals.
How to identify it
Anglesite is identified by its very high density, colorless to white appearance, adamantine to greasy luster, and white streak. It has a low hardness of 2.5 to 3 and good cleavage.
Its heft relative to size is a strong clue to its lead content, helping separate it from lighter colorless minerals like barite (though barite is also dense) and celestine.
Unlike its relative cerussite (lead carbonate), anglesite does not effervesce in dilute acid, a quick field test. Some anglesite fluoresces yellow under UV light.
Uses & significance
Anglesite is a minor ore of lead, exploited where it is abundant in oxidized ore zones, but galena remains the dominant lead source.
It has little industrial application beyond its contribution to lead extraction. Its main value today is as a mineral specimen, with transparent, gemmy crystals from Tsumeb and Morocco being especially desirable to collectors.
Because it is a lead compound, anglesite should be handled carefully, kept away from children, and never ingested. Faceted gems exist but are fragile collector curiosities only.
Frequently asked questions
How is anglesite different from cerussite?
Anglesite is lead sulfate and does not fizz in acid, while cerussite is lead carbonate and effervesces in dilute acid; both form from galena.
Why is anglesite so heavy?
Its high specific gravity comes from its lead content, making it noticeably dense for its size compared with common colorless minerals.
Where does the name anglesite come from?
It is named after the Isle of Anglesey in Wales, where the mineral was first described in the early 19th century.
Is anglesite dangerous?
It contains lead, so handle specimens with care, avoid dust and ingestion, and wash your hands afterward.
Anglesite guides
In-depth guides for identifying, valuing, and understanding Anglesite.
