Carnelian
Carnelian (Silicon Dioxide - SiO2 with iron oxide impurities)
Category
Browse sedimentary (silica rich mineral variety) specimens identified by the Rock Identifier community.
Carnelian
Carnelian (Silicon Dioxide - SiO2 with iron oxide impurities)
Petrified Wood
Silicified wood (Quartz, SiO2)
Jasper River Stone
Silicon Dioxide with Iron Oxide impurities (SiO2 + Fe2O3)
Quartz Geode
Silicon Dioxide (SiO2)
Chert (with Limestone matrix)
Silicon dioxide (SiO2)
Banded Iron Formation (BIF) / Tiger Iron
Banded Iron Formation containing Hematite (Fe2O3) and Magnetite (Fe3O4)
Picture Jasper
Silicon Dioxide (SiO2) with impurities
Blue Quartzite
Quartzite (specifically a variety enriched with blue-coloring minerals)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Obsidian
Volcanic glass (SiO2-rich amorphous silicate)
Amethyst
Quartz variety; chemical formula: SiO₂ (silicon dioxide) with Fe³⁺ impurities
Orthoclase Feldspar
Orthoclase (KAlSi3O8)
Satin Spar Selenite (Peach Calcite/Peach Gypsum)
Hydrated Calcium Sulfate (CaSO4·2H2O)
Quartz Crystal (specifically a Double-Terminated variety)
Silicon Dioxide (SiO2) - Low Quartz
Banded Calcite (often commercially sold as 'Mexican Onyx' or 'Honey Onyx')
Calcite (Calcium Carbonate, CaCO3)
Chert (Brecciated or Veined)
Silicon Dioxide (SiO2)
Basalt
Mafic Igneous Rock
Chert (and Flint)
Cryptocrystalline Quartz (SiO2)
Milky Quartz
Crystalline Silicon Dioxide (SiO2)
Zebra Jasper
Silicon Dioxide (SiO2) - Macro-crystalline Quartz/Chert with impurities
Fossil Coral
Fossilized Scleractinia or Tabulata (various genera/species)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Jasper (specifically Red Jasper/Chert)
Silicon Dioxide (SiO2) with iron oxide inclusions
Jasper (Red Jasper)
Jasper (SiO2 - Silicon Dioxide with iron inclusions)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert / Flint
Microcrystalline Quartz (SiO2)
Banded Calcite (often marketed as Caribbean Calcite)
Calcium Carbonate (CaCO3) + Aragonite
Limonite Sandstone
Ferruginous Sandstone (Hydrated Iron Oxide)
Pink Granite
Phaneritic Plutonic Felsic Rock (Granite)
Orange Calcite (often commercially sold as Honey Calcite or Aragonite)
Calcium Carbonate (CaCO3)
Chert (Nodule)
Chert (composition: SiO2)
Sandstone (Micaceous)
Arenite (primarily SiO2 with Phyllosilicates)
Blue Goldstone
Auraventurine (Synthetic glass with cobalt and copper inclusions)
Veined Quartz
SiO2 (Silicon Dioxide)
Chert (often called Flint)
Cryptocrystalline Quartz (SiO2)
Chert / River Pebble
Silicon Dioxide (SiO2)
Quartz (Milky/Crystalline variety)
Silicon Dioxide (SiO2)
Geode (Chert or Quartz Nodule)
Silicon Dioxide (SiO2)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix
Geode (Unopened)
Silica Concretion / Geode (Formula: SiO2 for quartz internal contents)
Chert (Jasper-like Silicate)
Microcrystalline quartz (SiO2)