Serpentine
Image: Darla Sondrol (CC0)
Mineral NameSerpentine
Chemical Formula(Mg,Fe)₃Si₂O₅(OH)₄
Mohs Hardness3.5
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite
Cleavagenone to poor
Fractureconchoidal/uneven
Specific Gravity2.55
Colorsgreen
Transparencytranslucent to opaque
Type LocalityLancaster County, Pennsylvania
Mineral GroupSilicates
Usescarving, architectural stone, collector specimens
Associated Mineralshydromagnesite, magnesite
Raritycommon
Description
This sample features predominately green Ni-rich serpentine, also known as genthite or garnierite, with visible yellow patches of hydromagnesite needles on magnesite. The serpentine exhibits a characteristic green hue, indicative of its nickel content.
Geological Context
Serpentine minerals typically form through the alteration of mafic-ultramafic igneous rocks via hydrothermal processes, a phenomenon known as serpentinization. This process involves the hydration and metamorphic transformation of olivine and pyroxene.
