Ludwigite - Encyclopedia
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 in the World
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