Prehnite
Ca2Al(AlSi3O10)(OH)2
Category
Browse mineral composite specimens identified by the Rock Identifier community.
Prehnite
Ca2Al(AlSi3O10)(OH)2
Hemimorphite
Hemimorphite (Zn4Si2O7(OH)2·H2O)
Tiger's Eye
Silicon Dioxide (Quartz pseudomorph after crocidolite), SiO2
Polished white agate or chalcedony bead
Microcrystalline quartz (SiO₂), likely chalcedony/agate with iron-oxide staining or a brown mineral inclusion
Geode (Unopened)
Crystalline Quartz or Chalcedony filled Geode (SiO2)
Lapis Lazuli
Complex rock primarily containing Lazurite (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2
Dalmatian Stone (commonly Dyed)
Dalmatian Jasper (Peralkaline igneous rock)
Quartz (Agate/Jasper pebble)
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz in Host Rock
Silicon Dioxide (SiO2) in Rhyolite or Granite matrix
Lazulite
Lazulite (Mg,Fe2+)Al2(PO4)2(OH)2
Shiva Lingam
Cryptocrystalline Quartz and Iron Oxide
Wishing Stone (Basalt/Metabasalt with Quartz-Feldspar Vein)
Veined Metabasalt / Veined Greywacke
Vesicular basalt (likely weathered volcanic rock)
Basalt, commonly composed of plagioclase, pyroxene, and olivine
Greenstone / serpentinized ultramafic rock (probable)
Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible magnetite and talc
Polished brecciated jasper (likely ribbon jasper)
Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide inclusions
Tumbled serpentine
Serpentinite; chiefly antigorite, lizardite, and/or chrysotile [Mg₃Si₂O₅(OH)₄]
Weathered iron-rich rock, possibly limonite-bearing sandstone or laterite
Limonite/goethite-rich ferruginous rock; exact identification requires testing
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Limonite Concretion
Hydrated Iron Oxide-Hydroxide, FeO(OH)·nH2O
Quartz Pebble
Silicon Dioxide (SiO2)
Limonite Concretion
Limonite (Hydrated iron(III) oxide-hydroxide) FeO(OH)·nH2O
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Quartz (Alluvial Pebbles)
Silicon Dioxide (SiO2)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Blue Quartzite (Dyed)
Silicon Dioxide (SiO2) with inclusions
Quartz pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Quartz (Iron-stained or Rose variant)
Silicon Dioxide (SiO2)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
White Quartz Pebble
Crystalline Silicon Dioxide (SiO2)
Jasper (specifically Polychrome or Desert Jasper)
Silicon Dioxide with impurities (SiO2)
Quartz / Quartzite
Quartz (Silicon Dioxide, SiO2)
Quartz in Matrix (possibly with Biotite or Hornblende)
Quartz (Silicon Dioxide, SiO2) in Granitic Matrix
Chert (Jasper)
Silicon Dioxide (SiO2)
Quartz / Calcite Vein Rock
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)