LANARKITE

    Class : Sulfates, chromates, molybdates
    Subclass : Anhydrous sulfates
    Crystal system : Monoclinic
    Chemistry : Pb2(SO4)O
    Rarity : Rare

Lanarkite is a rare lead sulfate from the oxidation zone of lead deposits that forms under basic conditions. It is also found in industrial slag. Its name derives from its locality of discovery : the Susanna mine, South Lanarkshire, Scotland. Lanarkite presents elongated crystals, with perfect lamellar cleavage, and frequently associated with other sulfates and carbonates, notably lead. It is gray, greenish-white or pale yellow in color. It is a very lead ore due to its rarity.

Main photo : Lanarkite from Susanna Mine, South Lanarkshire, Scotland, UK © Jeffrey Scovil

Labuntsovite from N'orkpakhk Mt, Khibiny Massif, Russia © Eugene & Sharon Cisneros
Labuntsovite from Aris, Windhoek Rural, Khomas, Namibia © Stephan Wolfsried
Labuntsovite from Aris, Windhoek Rural, Khomas, Namibia © Jason B. Smith
Labuntsovite from Poudrette quarry, Mont St-Hilaire, Quebec, Canada © Jason B. Smith

Lanarkite in the World

The largest known crystals come from the definition locality (Susanna mine, Scotland) and measure up to 5 cm. Very pretty transparent millimeter crystals are reported from the Redmond Mine (North Carolina).

Lanarkite in France

Lanarkite is known in remarkable crystals at the Lacore (or Laquorre) mine in Ariège, but the last discoveries date back to the 18th century. It is known in Asprières (Aveyron) but also in the slag of Crozet (Loire), Poullaouen (Finistère), Carnoët (Côtes-d'Armor) and Vialas (Lozère).

Twinning

Polysynthetic twins on [010] are known, but rare for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 2 to 2.5
Density : 6,92
Fracture : Splintery
Streak : White

TP : Translucent to transparent
RI : 1.928 to 2.036
Birefringence : 0.108
Optical character : Biaxial -
Pleochroism : None
Fluorescence : Yellow

Solubility : Nitric acid, potash

Magnetism : NoneRadioactivity : None