Chert (Iron-stained variant)
Microcrystalline Quartz (SiO2)
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Chert (Iron-stained variant)
Microcrystalline Quartz (SiO2)
Sandstone (Ferruginous/Red Sandstone)
Clastic sedimentary rock (primarily SiO2 with Fe2O3)
Chert (Tan/Brown)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Horse Chestnut (Buckeye seed)
Aesculus hippocastanum seed
Chert (specifically Pink/Tan Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Flint (Chert)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Fluorite
Fluorite (Calcium Fluoride - CaF2)
Quartz Vein in Host Rock (Gneiss/Schist)
Silicon Dioxide (SiO2) within a metamorphic matrix
Yellow Agate
Chalcedony (cryptocrystalline Quartz), SiO2
Aquamarine and clear quartz
Aquamarine (Be3Al2Si6O18), Quartz (SiO2)
Arsenopyrite in Quartz/Host Rock
Arsenopyrite (FeAsS)
Moqui Marble (Iron-Oxide Concretion)
Iron Oxide Concretion (Fe2O3)
Chert / Flint Nodules
Cryptocrystalline Quartz (SiO2)
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Chert Pebble with Quartz Veining
Microcrystalline Quartz (SiO2)
Chert (specifically Jasper or Flint variant)
Microcrystalline Quartz (SiO2)
Chert (White Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (vuggy variety)
Microcrystalline silica (SiO2)
Chert (specifically Yellow Jasper variety)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (variant Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Fossil Shark Tooth
Carcharodon or Carcharias fossil (Vertebrate Fossil)
Banded Chert (Flint)
Cryptocrystalline Quartz (SiO2)
Chert (variations include Flint/Jasper)
Cryptocrystalline Quartz (SiO2)
Natural White Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin - CaCO3
Limestone (Porous/Travertine variant)
Sedimentary Calcium Carbonate (CaCO3)
Citrine
Quartz (SiO2) - variety Citrine
Chert (Basanite / Flint)
Microcrystalline silica (SiO2)
Moss Agate
Moss Agate (a variety of Chalcedony, SiO ₂)
Red Swirl Beads (Likely Resin or Glass, simulating Red Jasper or Agate)
N/A (for the beads as pictured); Red Jasper: SiO2 (Chert variety); Red Agate: SiO2 (Chalcedony variety)
Fossiliferous Limestone (Crinoidal)
Calcium Carbonate (CaCO3) - Limestone containing bioclasts
Banded Chert
Microcrystalline silicon dioxide (SiO2)
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
Pink Chert (Brecciated Jasmine/Jasper)
Silicon Dioxide (SiO2)
Honey Calcite
Calcium Carbonate (CaCO3)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Unakite (Epidotized Granite)
Epidotized Granite (SiO2 with Ca2(Al,Fe)3(SiO4)3(OH))
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3)
Jasper Breccia
Silicon Dioxide (SiO2) - Brecciated Microcrystalline Quartz
Cullet (Slag Glass)
Amorphous Silica (SiO2) with various metal oxide colorants