Quincite (Rose-Opal)
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameQuincite (Rose-Opal)
Chemical FormulaMg₄Si₆O₁₅(OH)₂·6H₂O
Mohs Hardness2
Crystal Systemorthorhombic
Lusterdull
Streak Colorwhite
Cleavagenone
Fractureearthy
Specific Gravity2.1
Colorspink, rose-red, beige
Transparencyopaque
Type LocalityQuincy-sur-Cher, Bourges, Cher, Centre, France
Mineral GroupSilicates
Usescollector, pigment
Associated Mineralscalcite, quartz, clay minerals
Rarityuncommon
Description
A specimen featuring vibrant pink to rose-red Quincite, a variety of sepiolite, embedded within a lighter beige to brownish sedimentary matrix. The Quincite exhibits a dull to waxy luster and appears massive.
Geological Context
Quincite forms in sedimentary environments, often as an alteration product of magnesium-rich rocks or through precipitation from silica- and magnesium-rich waters. Its occurrence at Quincy-sur-Cher is within specific clay deposits.
