Gneiss
Gneiss
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Gneiss
Gneiss
Carnelian
Carnelian (variety of Chalcedony, SiO2)
Chert (and Limestone)
Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)
Chert / Microcrystalline Quartz
Chert (SiO2)
Chert (White Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Red Jasper (with Quartz Veins)
Jasper (var. chert, SiO₂)
Brachiopod Fossil in Limestone
Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)
Yellow Jasper
Chalcedony/Quartz (SiO2)
Blue-dyed howlite beads (likely)
Howlite, Ca₂B₅SiO₉(OH)₅, commonly dyed blue to imitate turquoise
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Travertine
Tufa limestone (CaCO3)
Chert (specifically Gray Chert)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified wood (primarily SiO2)
Chert (specifically Flint or Novaculite variant)
Chert (Microcrystalline Quartz, SiO2)
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
Ironstone Concretion
Ironstone (Siderite/Goethite/Hematite matrix)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Banded Chert
Silicon Dioxide (SiO2)
Chert (often called Flint or Jasper)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline quartz (SiO2)
Jadeite Jade
NaAlSi2O6 (Sodium Aluminum Silicate)
Chert (specifically Flint or Jasper variant)
Microcrystalline silica (SiO2)
Fossil Coral
Scleractinia or Anthozoa (Fossilized)
Petrified Wood Agate
Silicified Wood (primarily SiO2)
Pyrite
Iron Sulfide (FeS2)
Jasper
Silicon dioxide (Microcrystalline Quartz, SiO2)
Jasper (Iron-rich)
Silicon Dioxide (SiO2) with Fe2O3 (Hematite) inclusions
Chert / Flint
Chert (Cryptocrystalline Silica, SiO2)
Chert (Flint)
Chert (Microcrystalline Silica, SiO2)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Palm Wood Fossil
Palmoxylon
Fluorite (Rainbow Fluorite)
Calcium Fluoride (CaF2)
Shale
Shale (Sedimentary rock composed of mud/clay minerals)
Chert (often called Flint)
Chert (SiO2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
Aquamarine
Beryl (Be3Al2Si6O18)
Jasper
Silicon Dioxide (SiO2), Microcrystalline Quartz
Jasper
Silicon dioxide (SiO2)
Chert (specifically Flint or Common Chert)
Chert (Cryptocrystalline Silica, SiO2)
Fossilized Coprolite
Coprolite (fossilized feces)
Petrified Wood
Silicified Wood (SiO2)