Lussatite (Chalcedony pseudomorph)
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameLussatite (Chalcedony pseudomorph)
Chemical FormulaSiO2
Mohs Hardness6.5
Crystal Systemtrigonal
Lusterwaxy
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.6
Colorswhite, grey, brown, yellowish
Transparencytranslucent
Type LocalityMassal, Pont-du-Château, Puy-de-Dôme, France
Mineral GroupSilicates
Usescollector, scientific study
Rarityuncommon
Description
A fossilized snail shell (Helix Ramondi) pseudomorphed by lussatite, displaying a distinct spiral form with shades of white, grey, and yellowish-brown.
Geological Context
This pseudomorph formed during the Miocene epoch through the replacement of the original organic snail shell material by silica (lussatite/chalcedony) in a sedimentary or volcanic-sedimentary environment.
