LUDWIGITE

    Class : Carbonates, nitrates, borates
    Subclass : Borates
    Crystal system : Orthorhombic
    Chemistry : Mg2FeBO5
    Rarity : Quite common

Ludwigite (magnesian) forms a continuous series with vonsenite (ferriferous). It is found in iron-copper skarns, more rarely in tungsten-molybdenum, where it can constitute an industrial source of boron. It was named in honor of Ernst Ludwig, Professor of Chemistry at the University of Vienna (Austria). Ludwigite crystallizes in long, frequently acicular crystals, green-black to black in color, sometimes generating fibrous clusters, and is vaguely reminiscent of iron-bearing tourmalines.

Main photo : Ludwigite from Spring Mountain Mining District, Lemhi County, Idaho, USA © Salvatore Natalizia

Ludwigite from Brosso Mine, Piedmont, Italy © Flavio Giuseppe Taricco
Ludwigite in peridot from Sapat Gali, Pakistan © Rob Lavinsky
Ludwigite from Praskov'e-Evgen'evskaya, Russia © Andrey Gorshkov
Ludwigite from Corcolle Quarry, Lazio, Italy © Gianfranco Ciccolini

Ludwigite in the World

Philipsburg (Montana), Crestmore and Twin Lakes (California) and Spring Mountain (Idaho) which produced prismatic crystals of 4 cm. It is also known in various sites in Russia. Particularly spectacular fibroradiated masses were discovered in Brosso (Piedmont, Italy). It is also found in inclusions in Pakistani peridots.

Ludwigite in France

In France, ludwigite is reported in the mines of Costabonne (Pyrénées-Orientales).

Twinning

No twin known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 5
Density : 3.80
Fracture : Fibrous
Streak : Black to dark green

TP : Opaque
RI : 1.830 to 2.030
Birefringence : 0.140 to 0.180
Optical character : Biaxial +
Pleochroism : Strong
Fluorescence : None

Solubility : Acids

Magnetism : NoneRadioactivity : None