Melanophlogite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY 3.0)
Mineral NameMelanophlogite
Chemical FormulaSiO₂·nH₂O
Mohs Hardness6.5
Crystal Systemcubic
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2
Colorswhite, colorless, pale yellow, brownish
Transparencytransparent
Type LocalityFortullino, Rosignano Marittimo, Livorno Province, Tuscany, Italy
Mineral GroupSilicates
Usescollector
Associated Mineralsmagnesite, sulfur, calcite
Rarityrare
Description
The image displays small, rounded to botryoidal, whitish-grey spheres of Melanophlogite, one appearing translucent and the other more opaque, resting on a granular, yellowish matrix.
Geological Context
Melanophlogite is a rare silica polymorph that forms at low temperatures in gas-rich environments, often in cavities within serpentinites or limestones, incorporating guest molecules like hydrocarbons into its clathrate structure.
