Tektite (specifically Indochinite)
Tektite (Natural silica glass)
Category
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Tektite (specifically Indochinite)
Tektite (Natural silica glass)
Quartz (specifically Milky or Iron-stained Quartz)
Silicon Dioxide (SiO2)
Blue Chalcedony and Picture Jasper Beads
Blue Chalcedony (SiO2), Picture Jasper (SiO2)
Basalt
Extrusive mafic igneous rock
Milky Quartz
Silicon Dioxide (SiO2)
Chalcedony
Silicon dioxide (SiO2) - Microcrystalline quartz
Pyrite (Iron Pyrites)
Iron Sulfide (FeS2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Limestone (specifically Tufa or Travertine)
Calcium Carbonate (CaCO3)
Quartz (Variety: Citrine or Tumbled Chalcedony)
Silicon Dioxide (SiO2)
Brecciated Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Green Calcite
Calcium Carbonate (CaCO3)
Scoria (Lava Rock)
Scoria (Basaltic Scoria)
Chert (with Limestone matrix)
Chert (Silica: SiO2)
Amethyst
Silicon dioxide (SiO2) with iron impurities
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Feldspar (specifically Orthoclase)
Potassium Aluminum Silicate (KAlSi3O8)
Agate
Chalcedony (cryptocrystalline quartz)
Red Chert (Jasper)
Silicon Dioxide (SiO2)
Green Jasper
Silicon Dioxide (SiO2) with mineral inclusions
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Vesicular Basalt
Vesicular Basalt (Aphanitic Mafic Igneous Rock)
Granite
Plutonic felsic rock (Quartz, Feldspar, Mica)
Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Pebble (likely Quartz or Chert)
SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
Aura Quartz Geodes (Lab-Altered)
Silicon Dioxide (SiO2) with Metallic Vapor Deposition
Shale
Lutaceous sedimentary rock
Sandstone or Siltstone
Arenite (if sandstone)
Tree Agate
Dendritic Agate (Silicon Dioxide - SiO2)
Porphyry (specifically Porphyritic Basalt or Andesite)
Porphyritic extrusive igneous rock (Mg,Fe)2SiO4 (Olivine inclusions/Plagioclase Feldspar)
Amethyst
Quartz (SiO2) with trace iron impurities
Gneiss
Gneiss (High-grade metamorphic rock composed primarily of Quartz, Feldspar, and various Micas)
Orange Calcite
Calcium Carbonate (CaCO3)
Chalcedony (Common Opal variant or Agate)
Silicon Dioxide (SiO2)
Garnet (specifically Almandine)
Almandine (Fe3Al2(SiO4)3)
Basalt
Basalt (Mafic Extrusive Igneous Rock)
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Basalt
Afanitic Mafic Basalt
Basalt
Mafic volcanic rock (primarily plagioclase, pyroxene, and olivine)
River Stone / Pebble
Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)