What is Anglesite, Properties, Uses

Anglesite is a mineral composed of lead sulfate, with the chemical formula PbSO₄. It typically forms as a result of the oxidation of galena, a primary lead sulfide ore, in weathered environments. This makes it a secondary mineral, often found in the upper, oxidized zones of lead deposits.

It appears as orthorhombic crystals—sometimes prismatic, tabular, or pyramidal—or as massive, granular aggregates. Its color is usually white or colorless, though it can take on shades of gray, yellow, or even a bluish tint, often depending on impurities like leftover galena. Anglesite has a high specific gravity, around 6.3 to 6.4, due to its 74% lead content, making it notably dense. Its luster is described as adamantine, giving it a shiny, almost gem-like sparkle when well-crystallized, though its softness (2.5–3 on the Mohs scale) and good cleavage make it fragile and tricky to cut.

Anglesite crystals may contain impurities of galena, which can give the specimens a gray to black coloration. In some regions, anglesite forms as a pseudomorph after galena, resulting in crystals that appear to have an isometric form, though this is a false representation of their true structure. Some large anglesite specimens exhibit gray and black banding, which becomes visible when the specimen is sliced or polished.

The crystal habit of anglesite is typically tabular or thick tabular, often with pointed terminations. The primary crystal faces are usually striated. Anglesite can also occur in nodular, stalactitic, banded, crusty, reniform, or granular masses.

Anglesite was first identified as a distinct mineral in 1783 by William Withering in the Parys copper mine on the island of Anglesey, Wales—the source of its name. The mineral was later formally described by François Sulpice Beudant in 1832. While anglesite is occasionally mined as a lead ore in locations such as Australia and Mexico, where it occurs in large masses, it is more commonly sought after by mineral collectors for its striking crystals. Notable sources include Touissit, Morocco, and Tsumeb, Namibia. Although anglesite's brilliance and dispersion rival those of diamond, its softness and lead content make it unsuitable for use in jewelry.

Anglesite is named after its type locality, Anglesey, an island off the northern coast of Wales. It is a secondary mineral, typically forming in the oxidation zones of galena (lead sulfide) deposits.

Anglesite From: Touissit, Oujda-Angad Prov., Oriental Region, Morocco Photo Credit: Anton Watzl

Anglesite Properties

Formula: PbSO₄ A lead sulfate formed from oxidized galena in weathered lead deposits.

Color: Usually colorless, white, or yellow; also pale gray, blue, or green. Impurities like copper or iron cause the range, reflecting local geology.

Luster: Adamantine. Its diamond-like shine, from a high refractive index, attracts collectors.

Transparency: Crystals are transparent to translucent. Clear ones are prized; translucent ones hint at weathered growth.

Crystal System: Orthorhombic; 2/m 2/m 2/m. Three unequal axes shape its blocky or bladed crystals.

Crystal Habits: Bladed or tabular crystals dominated by two large pinacoid faces top and bottom and small prism faces forming a jutting angle on every side. Variations include complex forms or prismatic crystals with a rhombic cross-section when pinacoid faces diminish. Typically a flattened blade jutting from a host rock with a “false dome” termination (two faces of a rhombic prism). Also forms crusts, granular, or massive. Habits vary by growth—blades in cavities, crusts in tight spaces.

Cleavage: Perfect in one direction, less so in two others. Splits easily along one plane due to its layered structure.

Fracture: Conchoidal. Breaks with smooth, glass-like curves despite its softness.

Hardness: 2.5–3. Soft enough to scratch with a fingernail, limiting practical use.

Specific Gravity: Approximately 6.3+ (very heavy for translucent minerals). Lead content makes it dense, a key clue for miners.

Streak: White. Consistent white powder aids identification despite varied colors.

Anglesite from Touissit, Morocco: A gemmy, transparent crystal with mirror-like luster.

Associated Minerals: Galena, cerussite, barite, and limonite. Found with lead ores and oxidation products in mineralized zones.

Other Characteristics: Index of refraction is 1.88+ (very high); some specimens fluoresce yellow under UV light. High refraction boosts luster; fluorescence adds appeal for study.

Notable Occurrences: Tsumeb, Namibia; Australia; England; Mexico; and Touissit, Morocco. Famous lead-mining sites where anglesite thrives in oxidized layers.

Best Field Indicators: Crystal habit, density, high luster, and color.