Leadhillite

Leadhillit is a rarely occurring mineral from the mineral class of carbonates ( and nitrates). It crystallizes in the monoclinic crystal system with the chemical composition Pb4 [( OH) 2 | ( CO3) 2 | SO4 ] and developed mainly pseudo-hexagonal, tabular crystals that can be colored either colorless or white by foreign admixtures, gray yellow or pale blue. Rarely are also found in shelled aggregates.

Special Features

Since Leadhillit is isomorphic with Susannite and Macphersonit, he also has similar properties. So show some levels under UV light, a strong lemon-yellow fluorescence. On charcoal before the blowpipe swells Leadhillit heated slightly, turns yellow, and reduced to lead. In nitric acid dissolves the mineral roaring on with the release of carbon dioxide. The residual, poorly soluble lead sulphate forms a white precipitate.

Etymology and history

Was first discovered and described in 1832 by François Sulpice Leadhillit Beudant, who named it after its type locality Leadhills ( " Susannah Mine" ) in Scotland.

Classification

In the old classification of minerals (8th Edition) by Strunz the Leadhillit was in the department of " water clear sulfates with foreign anions " sorted. Since the new classification of minerals ( 9th Edition ) (after Strunz ), the mineral is, however, reclassified and is now in the department of " Carbonates with additional anions, without H2O by Cl, SO4, P04 ".

In the scheme of minerals by Dana Leadhillit is (translated: carbonates with various compositions ) in the department of " Compound carbonate with miscellaneous Formulae ".

Education and Locations

Leadhillit forms as a typical secondary mineral predominantly in the oxidation zone of lead deposits and takes place there in paragenesis with anglesite, cerussite, Linarit and other secondary lead minerals.

Locations include New South Wales, Queensland and Tasmania in Australia; the provinces of Limburg and Luxembourg in Belgium; Baden- Württemberg (Black Forest ), Lower Saxony ( St. Andrew Berg), North Rhine -Westphalia ( Bergisch land, country winner ), Rhineland -Palatinate (Eifel ), Saxony -Anhalt (resin) and Saxony (Erzgebirge) in Germany; different regions in France; Attica in Greece; different regions in the UK; different regions in Italy; Kyūshū in Japan; Oshikoto and Otjozondjupa in Namibia; Carinthia and Styria in Austria; Eastern Siberia, Murmansk Oblast and the Urals in Russia; the cantons of Uri and Valais in Switzerland; Gauteng and the Northern Cape in South Africa; Bohemia in the Czech Republic; and various regions in the United States.

Crystal structure

Leadhillit crystallizes in the monoclinic crystal system, space group P21 / a with lattice parameters a = 9.104 Å, b = 20.792 Å, c = 11.577 Å and β = 90.50 °, and eight formula units per unit cell.