Marble
Recrystallized Calcite (CaCO3)
Category
Browse mineraloid (human made geological specimen) specimens identified by the Rock Identifier community.
Marble
Recrystallized Calcite (CaCO3)
Obsidian
Volcanic Glass (felsic composition)
Quartz on Host Rock
Silicon Dioxide (SiO2)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Ambergris
Physeter macrocephalus excreta (Ambergris)
Quartz (Milky/Chalcedony variety)
Silicon Dioxide (SiO2)
Obsidian
Obsidian
Quartz
Silicon Dioxide (SiO2)
Mixed tumbled stone collection
Assorted minerals, likely including quartz, jasper, agate, and possibly obsidian or hematite
Chert (specifically Gray Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Agatized Fossil (Druzy Agate)
Silicon Dioxide (SiO2) replacing organic matter
River Cobble (Quartzite / Granitic Gneiss)
Metamorphic Quartzite / Granitic Gneiss
Phantom Quartz
Silicon Dioxide (SiO2) with inclusions
Gastropod Fossil (Snail Steinkern)
Class Gastropoda (internal mold)
Rough Quartz (or Quartzite pebble)
Silicon Dioxide (SiO2)
Chert (Jasper variation)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Green Opal (Prase Opal)
SiO2 · nH2O (Hydrated Silicon Dioxide)
Chert (Flint)
Silicon Dioxide (SiO2)
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
Tumbled pink quartz (probable rose quartz)
Quartz, silicon dioxide (SiO₂), commonly colored by trace elements and microscopic inclusions
Lepidolite in Mica Schist
K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2
Cat's Eye Shell (Shiva Shell)
Operculum of the Turbo petholatus (Tapestry Turban Snail), predominantly Calcium Carbonate (Aragonite)
Jasper
Microcrystalline Quartz (SiO2)
Carnelian (Red Chalcedony)
Silicon Dioxide (SiO2) with iron oxide impurities
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Clear Quartz
Silicon dioxide (SiO2)
Chalcedony (Chert/Flint)
Silicon Dioxide (SiO2)
Obsidian
Volcanic glass
Quartz (Tumbled)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz
Quartz (Silicon Dioxide, SiO2)
Chert (Flint/Jasper variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert
Microcrystalline quartz (SiO2)
Brecciated Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Quartz
Silicon Dioxide (SiO2)
Yellow Quartz
Silicon Dioxide (SiO2)
Siltstone Concretion
Carbonate-cemented Siltstone Concretion
Banded Iron Formation (Fragment)
Banded Iron Formation (BIF)
Chert Nodules in Limestone
Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)
Conglomerate (Pebble Conglomerate)
Conglomerate
Druzy Agate Geode
Silicon Dioxide (SiO2) - Microcrystalline Quartz