Granite
Granite (Phaneritic igneous rock)
igneous
Category
Organic Crystal (Mineraloid)
Browse organic crystal (mineraloid) specimens identified by the Rock Identifier community.
Schist
Mica Schist
metamorphic
Sandstone (Quartzose Sandstone)
Arenite (primarily SiO2 with minor Fe2O3)
sedimentary
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Pearl (likely Freshwater or Akoya Cultured)
Aragonite / Conchiolin composite (CaCO3)
Mineralloid (Organic gemstone)
Opal
Hydrated Silica (SiO2·nH2O)
mineral
Granite
Granite
igneous
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)
igneous
Gneiss
Gneiss (a type of metamorphic rock)
Metamorphic Rock
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2
igneous
Anthracite Coal
Anthracite (Carbon-rich mineraloid)
metamorphic
Banded River Rock / Gneiss (highly weathered)
Gneiss
Metamorphic rock
Tektite (Indochinite)
Tektite - High-silica amorphous glass (SiO2 + Al2O3)
mineraloid
Blue Opal Inlay (Simulated/Lab-created)
Hydrated Amorphous Silica (SiO2·nH2O) with polymer resin
mineraloid
Cobalt Glass Slug (Man-made Glass)
Amorphous Silica with Cobalt Oxide (SiO2 + CoO)
mineraloid
Fulgurite
Fulgurite (Lechatelierite-rich fused silica)
mineraloid
Pegmatite (likely Granitic Pegmatite)
Pegmatite (a coarse-grained igneous rock, often with granitic composition)
igneous
Garnetiferous Pegmatite
Pegmatite with Almandine Garnet and Muscovite
igneous
Obsidian and Green Calcite
Volcanic Glass and Calcium Carbonate (CaCO3)
igneous and sedimentary/mineral
Aragonite
Aragonite (CaCO3)
mineral
Granitic Pegmatite with Tourmaline and Sphalerite
Pegmatite containing Schorl (NaFe3Al6(BO3)3Si6O18(OH)4) and Sphalerite ((Zn,Fe)S)
igneous
Tanzanite (Rough)
Blue Zoisite (Ca2Al3(SiO4)3(OH))
mineral
Chert (White Variety)
Silicon Dioxide (SiO2)
sedimentary
Glass Nugget (Tumbled Glass)
Amorphous Silicon Dioxide (SiO2) with additives
mineraloid (man-made)
Granite (likely a river or beach pebble)
Granite (a felsic intrusive igneous rock primarily composed of quartz, feldspar, and mica)
Igneous
Granite
Granite (a plutonic igneous rock)
Igneous
Slag (Industrial Glass)
Artificial Vitreous Silicate
mineraloid (anthropogenic)
Amber
Succinite (fossilized resin)
mineral
Fossil Shark Tooth (Sand Tiger or Mackerel Shark)
Carcharias sp. or Otodus sp. replaced by Hydroxylapatite/Calcium Carbonate
sedimentary
Chalk
CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock
Sedimentary
Granite
Granite (a plutonic igneous rock)
Igneous
Amber
Succinite (specifically for Baltic Amber), Formula: C10H16O
Organic Gemstone (often associated with Sedimentary sequences)
Granite
Granite
igneous
Granite
Granite (a plutonic igneous rock composed of quartz, feldspar, and mica)
igneous
Granite
Granite (a plutonic igneous rock composed primarily of quartz, feldspar, and mica)
igneous
Green Moss Agate / Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions
sedimentary
Fossiliferous Limestone with Rugose Coral
Calcium Carbonate (CaCO3) featuring Rugosa (extinct order of solitary and colony corals)
sedimentary
Red Jasper (possibly Petrified Wood)
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary (secondary formation)
Granite
Granite (a common rock name, not a single mineral species, composed primarily of quartz, feldspar, and mica/amphibole)
igneous
Septarian Nodule or Mud Crack Fossil
Septarian Nodule (Concretion)
sedimentary
Chert (with Iron Staining)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (River Cobble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary