Prehnite
Prehnite Ca2Al2Si3O10(OH)2
Category
Browse mineral, organic gemstone specimens identified by the Rock Identifier community.
Prehnite
Prehnite Ca2Al2Si3O10(OH)2
Black Star Diopside
Diopside (CaMgSi2O6) with asterism
Pink Tourmaline in Quartz Matrix
Elbaite (Na(Li,Al)3Al6(Si6O18)(BO3)3(OH)4) in Quartz (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Rough Emerald
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
Dolomite on Prehnite (Saddle-shaped Dolomite)
Dolomite [CaMg(CO3)2] on Prehnite [Ca2Al(AlSi3O10)(OH)2]
Rough Emerald/Green Beryl
Beryl (Be3Al2(SiO3)6) with trace amounts of Chromium or Vanadium
Amazonite
Triklinic Potassium Feldspar (KAlSi3O8)
Amethyst
Silicon Dioxide (SiO2 with iron impurities)
Septarian Nodule (Dragon Stone)
Septarian Nodule (Calcium Carbonate/Aragonite/Calcite Concretion)
Olivine (Peridot)
Olivine (Magnesium Iron Silicate, (Mg,Fe)2SiO4)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Pink Feldspar (Orthoclase)
Orthoclase Feldspar (KAlSi3O8)
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Chrysocolla
Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O)
Garnet (Almandine)
Almandine (Fe3Al2(SiO4)3)
Blue Kyanite
Kyanite (Al2SiO5)
Alexandrite in Matrix
Chrysoberyl (BeAl2O4 with Chromium impurities)
Pyrite in Quartz
Iron Sulfide (FeS2) on Silicon Dioxide (SiO2)
Olivine in Basalt (Peridotite Xenolith)
Forsterite-rich Olivine (Mg2SiO4) in Aphanitic Basalt
Shale or Mudstone (Based on appearance)
Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)
Amethyst (Purple), Sulfur (Yellow), and Blue Apatite
SiO2 (Quartz), S (Native Sulfur), Ca5(PO4)3(F,Cl,OH) (Apatite Group)
Quartz
Silicon dioxide (SiO2)
Amethyst
Amethyst (Silica mineral, SiO2)
Tiger's Eye
Tiger's Eye (Pseudomorph of Quartz after Crocidolite), SiO2
Rhodonite
Manganese silicate (Mn,Fe,Mg,Ca)SiO3
Smoky Quartz
Smoky Quartz (Silicon Dioxide - SiO2)
Diamond (in Jewelry)
Carbon (C)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz (Milky/Granular)
Silicon Dioxide (SiO2)
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)
Blue Apatite
Fluorapatite / Chlorapatite [Ca5(PO4)3(F,Cl,OH)]
Smoky Quartz
Silicon Dioxide (SiO2)
Purple Banded Agate
Cryptocrystalline Quartz (SiO2)
Red Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
Rhodonite
Rhodonite (Mn,Fe,Mg,Ca)SiO3
Milky Quartz
Silicon Dioxide (SiO2)
Yellow Jasper
Tectosilicates (SiO2) with Goethite/Iron oxide inclusions
Sodalite
Sodalite (Na8Al6Si6O24Cl2)
Carnelian Agate
Silicon Dioxide (SiO2) with iron oxide impurities