Anglesite Composition, Crystallization & Structure

Composition. Lead sulphate, PbSO4 = Sulfur trioxide 26.4, lead oxide 73.6.

Crystallization. Orthorhombic. Crystal habit often similar to that of barite but much more varied. Crystals may be prismatic parallel to all three of de crystals axes and frequently show many forms, with a complex development.

Structure. Crystallized. Also massive, granular to compact. Frequently earthy, in concentric layers about a nucleus of galena.

Physical properties. Perfect cleavage parallel to base and prism. H. = 2.75-3. G. = 6.12-6.39 (unusually high). Adamantine luster when pure and crystalline, dull when earthy. Colorless, white, pale shades of yellow, green and blue. May be colored dark gray, etc., by impurities. Transparent to opaque.

Test. Easily fusible at 2.5. On charcoal with sodium carbonate reduced to a lead globule with yellow to white coating of lead oxide. Fused with sodium carbonate and charcoal dust gives a residue, which, when moistened, produces on a clean silver surface a dark stain of silver sulphide. Recognized by its high specific gravity, its adamantine luster and frequently by its association with galena.

Occurrence. Anglesite is a common lead mineral of secondary origin. It is formed through the oxidation of galena, sometimes directly to the sulphate as is shown by the concentric layers of anglesite

Found at times surrounding a core of unaltered galena, or sometimes by an intermediate solution and subsequent recrytallization. Found in the upper, oxidized portion of lead veins, associated with galen, serussite, sphalerite, smithosite, calamine, iron oxides, etc. Notable localities for its occurrence are Monte Poni, Sardinia; Is land of Anglesey, Wales; from Derbyshire; at Leadhills, Scotland. From Sidi -Amor-ben-Salem in Tunis; near Otavi, South West Africa; Broken Hill, New South Wales; Dundas, Tasmania. Occurs in the United States at Phoenixville, pennsyvania; Tintic distric, Utah; Coeu d´ alene distric, Idaho.

Name. Named from the original locality on Island of Anglesey.

Use. An ore of lead.