Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
mineral
Category
Mineral (Organic Gemstone)
Browse mineral (organic gemstone) specimens identified by the Rock Identifier community.
Dendritic Agate (or Dendritic Opal)
SiO2 (for Agate), SiO2·nH2O (for Opal)
Mineral
Quartz (Chatoyant or Milky variety)
Silicon Dioxide (SiO2)
mineral
Chrysocolla
Chrysocolla; (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Ironstone Concretion (Ironstone Gourd)
Limonite/Goethite Concretion (FeOO(H))
sedimentary
Chert (specifically Flint or Gray Chert)
Silicon Dioxide (Microcrystalline Quartz), SiO2
sedimentary
Howlite
Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)
mineral
Sunstone
Oligoclase or Andesine (Plagioclase Feldspar) - (Ca, Na)((Al, Si)2Si2O8)
mineral
Quartz (Peach/Orange variety)
Silicon Dioxide (SiO2)
mineral
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
mineral
Chert (often called Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Peridot
Olivine ((Mg, Fe)2SiO4)
mineral
Turquoise (Dyed Howlite or Magnesite imitation)
Hydrated phosphate of copper and aluminum / CuAl6(PO4)4(OH)8·4H2O
mineral
Amber (Black)
Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)
Mineraloid
Pegmatite (Granitic)
Granitic Pegmatite containing Quartz, Feldspar, and Tourmaline (Schorl)
igneous
Nuummite
Nuummite (intergrowth of orthoamphiboles Anthophyllite and Gedrite, (Mg,Fe)7Si8O22(OH)2)
metamorphic
Peridot
Olivine (Mg, Fe)₂SiO₄
mineral
Dendritic Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O) with Manganese or Iron Oxide inclusions
mineral
Chert (Flint)
Chert (Silicon Dioxide, SiO2)
sedimentary
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Brown Jasper (Likely)
Jasper (Cryptocrystalline Silicon Dioxide - SiO2)
Mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Chert / Flint
Chert (varietal name for microcrystalline quartz). Chemical formula: SiO₂
Mineral
Rhodonite
Rhodonite (Manganese silicate, (Mn,Fe,Mg,Ca)SiO3)
mineral
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Yellow Beryl (Heliodor)
Beryllium aluminum silicate (Be3Al2Si6O18)
mineral
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
mineral
Rutilated Quartz
Silicon Dioxide (SiO2) with Titanium Dioxide (TiO2) inclusions
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Opal
Hydrated silica (SiO2·nH2O)
mineraloid
Shale
Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Hemimorphite on Limonite Gossan
Hemimorphite (Zn4Si2O7(OH)2·H2O) on Limonite matrix
mineral
Dragon Stone
Ohko Stone (Argillaceous sedimentary rock)
sedimentary
Chert (and Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Ferruginous Sandstone (with possible trace fossils)
Arenite with Iron-Oxide Cement (SiO2 with Fe2O3)
sedimentary
Garnet (Almandine)
Almandine, Fe3Al2(SiO4)3
metamorphic
Petrified Wood (Silicified Wood)
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
mineral
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
mineral