MELANOPHLOGITE
Class : Silicates
Subclass : Tectosilicates
Crystal system : Tetragonal
Chemistry : SiO2 n(C, H, O, S)
Rarity : Very rare
Melanophlogite is a particular silicate in which the voids available between the SiO4 tetrahedra are occupied by organic compounds and sometimes sulfur, essential for the stability of the crystalline structure. Its name comes from the Greek melanos (black) and phlogai (to burn) because some samples of this mineral drown when burned. Crystals are rare (usually millimeter-size pseudocubes). Melanophlogite generally occurs in rounded polycrystalline aggregates with complex shapes, evoking drops, and building fine encrustations. Organic compounds are present in varying amounts (7 to 12%). Melanophlogite is colorless when pure, but often pale yellow to dark red-brown, due to the presence of impurities. It is a rare mineral, little known to collectors, which has no particular use.
Main photo : Melanophlogite on lussatite from Mine des Rois, Dallet, Puy-de-Dôme, France
Melanophlogite in the World
Melanophlogite in France
The best melanophlogite crystals come from France and more particularly from the Limagne Basin in Puy-de-Dôme. They can form individual centimeter-sized pseudocubes and stacked groups of several centimeters. It is systematically found associated with lussatite, chalcedony and bitumen on the Mine des Rois deposit in Dallet.
Twinning
No twin known for this mineral species.
Fakes and scams
No fake recorded for this mineral species.
Hardness : 6.5 to 7
Density : 2
Fracture : Conchoidal
Trace : White
TP : Translucent to transparent
IR : 1.425 to 1.457
Biréfringence : Very low
Optical character : Uniaxial +
Pleochroism : None
Fluorescence : White
Solubility : Hydrofluoric acid
Magnetism : None
Radioactivity : None