Limestone
Calcium Carbonate (CaCO3)
Category
Browse sedimentary (microcrystalline silicate) specimens identified by the Rock Identifier community.
Limestone
Calcium Carbonate (CaCO3)
Yellow Quartzite River Cobble
Meta-quartzite (SiO2 with iron oxide staining)
Orange Quartzite (River Pebble)
Quartzite (primarily SiO2)
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Graphite-veined Quartzite
Meta-sedimentary Quartzite with Carbonaceous/Graphitic Inclusions (SiO2 + C)
Dalmatian Jasper (or Dalmatian Stone)
Dalmatian Stone (A peralkaline felsite composed of feldspar, quartz, and sodic amphibole)
Chalcedony
Chalcedony (a microcrystalline variety of Quartz, SiO2)
River Cobble (likely Quartzite or Limestone)
SiO2 (Quartzite dominant) or CaCO3 (Limestone dominant)
Banded Calcite (often sold as Onyx)
Calcite (Calcium Carbonate, CaCO3)
Quartz Vein in Host Rock
Quartz (SiO2) in Mafic or Sedimentary Matrix
Jasper
Silicon dioxide (SiO2)
Agate and Amethyst (Quartz variants)
Silicon Dioxide (SiO2) - Microcrystalline Quartz and Crystalline Quartz
Red Jasper
Jasper (a cryptocrystalline variety of Quartz, SiO₂)
Greenschist / Migmatite
Regional Metamorphic Complex (Facies: Greenschist to Amphibolite)
Jasper Breccia
Brecciated Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)
Petrified Wood
Silicified wood (primarily Silicon Dioxide - SiO2)
Banded Iron Formation
Banded Iron Formation (BIF)
Banded Jasper (Chert)
Silicon Dioxide (SiO2) - variety of Chalcedony
Carnelian
Carnelian (a variety of Chalcedony, which is a microcrystalline quartz, SiO2)
River Pebble (Greywacke or Basaltic)
Massive Greywacke or Basaltic Andesite
River Pebble (Likely Quartzite or Chert)
Silicon Dioxide (SiO2)
Ironstone Concretion (likely)
Goethite/Hematite/Limonite cemented sediment
Limestone (Cliff Formation)
Limestone (predominantly CaCO3 as calcite)
Chalk / Sedimentary Limestone
Calcium Carbonate (CaCO3) - Biogenic Sedimentary Rock
Limestone
Calcium Carbonate (CaCO3)
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
Chert Nodule in Limestone
Chert (Microcrystalline Quartz, SiO2) and Limestone (Calcium Carbonate, CaCO3)
Concrete with Aggregate
Composite construction material; primary matrix is Calcium Silicate Hydrate (C-S-H)
Carnelian
Carnelian (a variety of Chalcedony, SiO ₂)
Zebra Marble
Metamorphosed Alabaster/Limestone (CaCO3)
Quartzite and Chert
Silicon Dioxide (SiO2)
Aventurine (Green)
Silicon Dioxide (Quartz) with inclusions typically of Fuchsite; SiO2
Corundum
Corundum (Al2O3)
Petrified Wood
Silicified Wood (primarily SiO₂ - Silicon Dioxide)
Petrified Wood
Silicified wood (Quartz, SiO2)
Limestone (specifically Fossiliferous or Crinoidal Limestone)
Calcium Carbonate (CaCO3) - Calcite Rock
Carnelian
Carnelian (a variety of Chalcedony, SiO2)
Red Jasper
Jasper (a variety of Chalcedony, SiO₂ with impurities)
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Weathered Quartzite or Chert Pebble
Silicon Dioxide (SiO2)
Jasper
Silicon Dioxide (SiO2)
Geode (Unbroken)
Silicon Dioxide (SiO2) usually as Microcrystalline Quartz or Chalcedony