Chert (Arrowhead)
Chert (primarily Microcrystalline Silica, SiO2)
Category
Browse metamorphic rock (formed from a fibrous crocidolite asbestos) specimens identified by the Rock Identifier community.
Chert (Arrowhead)
Chert (primarily Microcrystalline Silica, SiO2)
Basalt Cobble
Vesicular Basalt (Mafic Extrusive)
Quartz Vein in Host Rock (Pebble)
Quartz (SiO2) with sandstone or siltstone matrix
Quartz (Iron-stained or Ferruginous)
Silicon Dioxide (SiO2)
Sandstone (Tumbled/River Pebble)
Arenite (composed primarily of SiO2)
Aragonite (variety 'Flos Ferri')
Aragonite (CaCO3)
Labradorite
Labradorite ((Ca, Na)(Al, Si)4O8)
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Smoky Quartz (Faceted Beads)
Silicon Dioxide (SiO2)
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
Sandstone, Quartzite, and River Pebbles
Silicon Dioxide (SiO2) based Sedimentary/Metamorphic structures
Smoky Quartz
SiO2 (Silicon Dioxide)
Basalt
Extrusive mafic igneous rock
Rutilated Quartz
Quartz (SiO2) with Rutile (TiO2) inclusions
Amethyst
SiO2 (Silicon Dioxide with Iron impurities)
River Rocks (Black)
Various lithologies (e.g., basalt, chert, obsidian for black varieties), mechanically rounded clasts
Epidote in Quartz (Unakite-like specimen)
Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH)) in Quartz (SiO2)
Quartz (Milky or Citrine-tinted)
Silicon Dioxide (SiO2)
Pink Granite
Phaneritic Felsic Igneous Rock (Granite, rich in Potassium Feldspar)
Slate
Slate (Foliated metamorphic rock consisting mainly of quartz and muscovite or illite)
Muscovite Mica (with Quartz)
Muscovite (KAl2(AlSi3O10)(OH)2)
Garnet (Almandine)
Almandine Garnet (Fe3Al2(SiO4)3)
Slate
Foliated Metamorphic Rock (primarily composed of quartz, illite, chlorite, and micas)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) in matrix
Labradorite
Labradorite (a calcium-enriched feldspar mineral), (Ca, Na)(Al, Si)4O8
Sodalite
Sodalite [Na8(Al6Si6O24)Cl2]
Prasiolite and Quartz Crystal Cluster
Quartz (SiO2); Prasiolite is a variety of Quartz
Quartzite (or Milky Quartz pebble)
Quartzite (Metamorphosed Sandstone) / Silicon Dioxide (SiO2)
Green Aventurine
Aventurine Quartz (SiO2 + Fuchsite mica)
Aquamarine with Sunstone
Aquamarine (Be3Al2Si6O18), Sunstone (Na,Ca)Al(Si,Al)Si2O8
Vesicular Basalt (Scoria)
Vesicular Basalt
Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
Citrine
SiO2 (Silicon Dioxide)
Quartz (Drusy/Crystalline)
Silicon Dioxide (SiO2)
Quartz (Clear Quartz and Rose Quartz variants)
Silicon Dioxide (SiO2)
Quartz (Milky or Grainy Variety)
Silicon Dioxide (SiO2)
Granite
Granite
Granodiorite with Quartz Veining
Granodiorite (containing Plagioclase Feldspar, Quartz, and Biotite/Hornblende) with Quartz (SiO2) veins
Druzy Quartz on Matrix (likely Limestone or Sandstone)
Silicon Dioxide (SiO2) with various trace impurities
Quartz (Amethyst variety)
Silicon Dioxide (SiO2)