White Marble
Metamorphosed Limestone (principally CaCO3)
metamorphic
Category
Sedimentary (Microcrystalline Silicate)
Browse sedimentary (microcrystalline silicate) specimens identified by the Rock Identifier community.
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Glauconitic Sandstone
Glauconitic Sandstone (Greensand)
sedimentary
Ruby in Kyanite
Corundum in Disthene (Al2SiO5 + Al2O3)
metamorphic
Rounded river pebble
Likely lithic sandstone or weathered quartz-rich rock; exact identification requires testing
sedimentary
Sandstone
Arenite
sedimentary
Siltstone
Siltstone (composed of mixed silicate minerals and clay)
sedimentary
Sea Glass
Man-made silicate glass weathering product
sedimentary
Bentonite Clay
Al2O3·4SiO2·H2O (Hydrous aluminum silicate)
sedimentary
Quartz Vein in Host Rock
Silicon dioxide (SiO2) veining in silicate matrix
sedimentary
Coprolite
Coprolite (fossilized feces)
fossil
Ruby Zoisite
Anyolite (Calcium aluminium silicate with Chromium/Corundum inclusions)
metamorphic
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Marble
Recrystallized Calcite (CaCO3)
metamorphic
Polished chrysocolla-bearing copper mineral specimen
Chrysocolla, Cu₂H₂Si₂O₅(OH)₄·nH₂O, likely mixed with malachite and limonite/goethite
mineral
Banded Gneiss (with Quartz Vein)
Gneiss (SiO2 and varied Silicates)
metamorphic
Polished magnetite-rich ironstone (possible magnetite pebble)
Magnetite, Fe₃O₄; possibly magnetite-bearing basalt or ironstone
mineral
Mixed polished river stones
Likely quartz, quartzite, chert/jasper, and possibly limestone or marble
mineral
Small weathered rock fragment
Indeterminate; possibly carbonate-rich sandstone or limestone
sedimentary
Greenstone / Serpentinite Pebble
Serpentinite (Hydrated Magnesium Silicate, Mg3Si2O5(OH)4)
metamorphic
Fossiliferous limestone with shell fragments
Bioclastic calcarenite; predominantly calcite (CaCO₃), with fossil mollusk material
sedimentary
Bumblebee Jasper
Calcite with Arsenic and Sulfur inclusions
sedimentary
Conglomerate
Clastic Sedimentary Conglomerate (SiO2 primarily)
sedimentary
Schist
Metamorphic Rock (Schist)
metamorphic
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone (Ferruginous)
Clastic Sedimentary Rock (SiO2 with Fe2O3)
sedimentary
Luminous Stone (Glow-in-the-dark Synthetic/Man-made Stone)
Strontium Aluminate tinted glass or resin (Crystalline silicate/oxide mix)
mineral (synthetic)
Milky quartz pebble
Quartz (silicon dioxide, SiO₂)
mineral
Almandine Garnet
Iron aluminum silicate - Fe3Al2(SiO4)3
metamorphic
Quartzite
Quartzite (SiO2)
metamorphic
Kyanite (within Quartz)
Kyanite (Al2SiO5) in crystalline Quartz base (SiO2)
metamorphic
Aquamarine (Pendant) and Jasper (Beads)
Beryllium aluminum silicate (Be3Al2Si6O18) with Chalcedony (SiO2)
mineral
Chert / Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Green Moss Agate
Agate (Silicon Dioxide - SiO2) with inclusions of hornblende or chlorite
mineral
Weathered limestone fragment
Limestone, predominantly calcite (CaCO₃)
sedimentary
Sandstone (Ferruginous)
Arenite (complex silicate composition with iron oxides)
sedimentary
Tumbled jasper or chert
Microcrystalline quartz (SiO₂), commonly jasper/chalcedony
mineral
Sandstone (Ferruginous)
Arenite (with iron oxide cement)
sedimentary
Tumbled ocean jasper (orbicular jasper), likely brecciated variety
Jasper: microcrystalline quartz (SiO₂) with iron-oxide staining and other silicate inclusions
metamorphic
Riverstone (Quartzite/Granite Cobble)
Silicon Dioxide (SiO2) based Quartzite or Silicate-rich Granite
metamorphic or igneous
Bloodstone (Heliotrope)
Silicon Dioxide (SiO2) with iron silicate and iron oxide inclusions
Mineral
Porcelain (Kaolin-based)
Alumina silicate ceramic (composed primarily of Kaolinite: Al2Si2O5(OH)4)
metamorphic (man-made/engineered)