PARALAURIONITE

    Class : Halides
    Subclass : Oxychlorides
    Crystal system : Monoclinic
    Chemistry : PbCl(OH)
    Rarity : Rare

Paralaurionite is a chloride from the surface oxidation zone of lead deposits. Its formation requires chlorine : it is therefore found in environments located near the marine coast or in closed evaporite basins. It is also found in certain industrial slags. Its name comes from the Greek para (near) and its dimorphic relationship with laurionite. Paralaurionite forms lamellar to tabular crystals, sometimes elongated, white to grayish, sometimes yellowish, with a strong adamantine luster. It is associated with other secondary lead minerals including abundant chlorides (penfieldite, phosgenite, etc...).

Main photo : Paralaurionite from Lavrion, Greece © Henry Minot

Paralaurionite on leadhillite from Mammoth St-Antony, Tiger, Arizona, USA © Rock Currier
3 cm paralaurionite from Touissit, Morocco © Rob Lavinsky
Paralaurionite from Lavrion, Greece © Henk Smeets
Paralaurionite from Menez-Plom, Côtes-d’Armor, France © Yannick Vessely

Paralaurionite in the World

Beautiful pale yellow twinned crystals of 2.5 cm come from the Tiger district (Arizona), and from Shepton Mallet, in Somerset England, where cleavable sulfur yellow masses of 5 cm have been discovered. Good tabular crystals of 1 cm come from slag from the Laurion mines (Greece). The Touissit lead mine (Morocco) also provided large lamellar crystals up to 3 cm.

Paralaurionite in France

In France, paralaurionite is known at the Lescure mine near Mayres (Ardèche) but also in the slag of Poullaouen (Finistère) and in those of Menez-Plom (Côtes-d'Armor).

Twinning

Contact twins on {100} are common, forming crystals with an orthorhombic appearance.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 3
Density : 6.15
Fracture : Undetermined
Streak : White

TP : Translucent to transparent
RI : 2.050 to 2.200
Birefringence : 0.150
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None

Solubility : Nitric acid

Magnetism : NoneRadioactivity : None