Pyrite
Pyrite (FeS2)
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Pyrite
Pyrite (FeS2)
Amber
Succinite (approximate formula C10H16O)
Amber (Dark/Black Variety)
Succinite (Resinite), C10H16O
Chert Nodule
Chert (Cryptocrystalline variety of Quartz, SiO2)
Calligraphy Stone
Mariam Jasper (Fossiliferous Limestone with Hematite and Iron)
Moss Agate
Chalcedony (Silicon Dioxide / SiO2)
Lake Superior Agate
Banded Chalcedony (Silicon Dioxide / SiO2)
Sandstone (with carbonaceous plant fragments)
Arenite (composed primarily of SiO2)
Chert (White Flint)
Silicon Dioxide (SiO2)
Red Coral
Corallium rubrum
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Limestone (Weathered)
Calcium Carbonate (CaCO3)
Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
Metal Alloy (Likely Pewter or Sterling Silver)
Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).
Serpentine
Serpentinite (a rock composed primarily of serpentine minerals like antigorite, chrysotile, and lizardite; general formula (Mg, Fe)3Si2O5(OH)4)
Chert (Smooth River Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Amber (specifically Red or Cherry Amber)
Succinite (Resinite); Chemical formula: C10H16O
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Amber
Fossilized Tree Resin (Generic formula roughly C10H16O)
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Unakite
Epidotized Granite
Chert (Iron-stained or Dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Limonite-stained Chert
Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)
Brachiopod Fossil in Limestone
Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)
Chert (with Quartz Vein)
Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)
Chert (and Jasper blend)
Chert (Microcrystalline Quartz, SiO2)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Fossiliferous Limestone (Coquina / Shell Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
Jasper
Jasper (Silicon Dioxide, SiO2)
Chert (Black Chert / Flint)
Silicon Dioxide (SiO2)
Chert (Jasper transition)
Microcrystalline Quartz (SiO2)
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Travertine
Calcareous Tufa / Travertine (CaCO3)
Red Jasper
Silicon dioxide (SiO2) with iron oxide (Fe2O3) inclusions
Chert (Flint Nodules)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (varietal Chalcedony or Flint)
Silicon dioxide (SiO2) - Microcrystalline Quartz
Chert Pebble
Microcrystalline or Cryptocrystalline Quartz (SiO2)