Augelite - Encyclopedia

    Class : Phosphates, arsenates, vanadates
    Subclass : Anhydrous phosphates
    Crystal system : Monoclinic
    Chemistry : Al2(PO4)(OH)3
    Rarity : Fairly rare


Augelite is an aluminum phosphate present in certain high temperature hydrothermal veins, pegmatites, as well as in metamorphic phosphate and aluminous rocks. Its name comes from the Greek auge (brilliant), in reference to the pearly luster of its cleavage planes. The crystals are tabular, sometimes prismatic, rarely acicular ; they are colorless, yellowish, greenish or pinkish. The augelite also forms cleavable masses, sometimes of significant size. It is a mineral which is not used in any particular field and which remains relatively unknown to collectors.

Augelite in the World

The finest known samples are superb clusters of 2 cm bright green crystals, accompanied by quartz twins from the Mundo Nuevo mining complex (Peru). Beautiful 2 cm crystals embedded in mineralized andalusite lenses are known from the Champion mine, near Benton (California). Augelite also occurs as small crystals and cleavable masses in pegmatites from Newry (Maine) and Palermo and Smith (New Hampshire) as well as Keystone (South Dakota). It is found in the metamorphic limestones of Rapid Creek (Canada) in pale yellow-green crystals of 5 mm. It is relatively common in the cassiterite and silver veins of Oruro, Llallagua and Machacamarca (Bolivia) where its crystals can exceed 3 cm.

Augelite in France

In France, augelite is known in the pegmatites of Collioure (Pyrénées-Orientales).

Twinning

A twin seems to be present for this species, but we have not found any information about it except for a photo of a sample known to be twinned from Estaño Orcko mine (Bolivia) of Rob Lavinsky's collection (photo on the right).

Fakes and treatments

No fake recorded for this mineral species.



Hardness : 4.5 to 5
Density : 2.7
Fracture : Irregular
Trace : White




TP : Translucent to transparent
IR : 1.574 to 1.588
Biréfringence : 0.015
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None


Solubility : Hydrochloric acid

Magnetism : None
Radioactivity : None