Eskolaite - Encyclopedia
Class : Oxides and hydroxides
Subclass : Oxides
Crystal system : Trigonal
Chemistry : Cr2O3
Rarity : Very rare
Eskolaite is an extremely rare chromium oxide which is mainly found in chrome-bearing tremolite skarns, more rarely in metaquartzites and chlorite schists. It is also known in pebbles of fluvial alluvium and glacial moraines. Its name was given to it in honor of Pentii Eelis Eskola, Professor of Petrology at the University of Helsinki (Finland). Eskolaite appears in shiny rhombohedra of dark green to greenish black.
Main photo : Eskolaite from Outokumpu mining district, Outokumpu, North Karelia, Finland © Stephan Wolfsried
Eskolaite in the World
Twinning
No twin known for this mineral species.
Fakes and treatments
No fake listed for this mineral species.
Hardness : 8 to 8.5
Density : 5.18
Fracture : Undeterminated
Streak : Light green
TP : Translucent to opaque
RI : Undeterminated
Birefringence : Undeterminated
Optical character : Uniaxial
Pleochroism : Visible
Fluorescence : None
Solubility : Insoluble
Magnetism : None
Radioactivity : None