Greenstone (Greenschist facies)
Greenschist (composed primarily of Chlorite, Actinolite, and Epidote)
metamorphic
Category
Igneous, Sedimentary, Or Metamorphic (Mineral Based)
Browse igneous, sedimentary, or metamorphic (mineral based) specimens identified by the Rock Identifier community.
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Blue Sapphire
Corundum (Al2O3)
mineral
Tumbled yellow quartz (likely citrine)
Quartz, silicon dioxide (SiO₂), iron-colored variety
mineral
Given the appearance, it's likely a fragment of an igneous or metamorphic rock composed of multiple minerals. Without specific diagnostic features, it's difficult to give a common name other than 'crystalline rock fragment'. If pressed to guess based on the granular, somewhat light and dark speckled appearance, it could be a fragment of granite or a related intrusive igneous rock.
As a rock fragment, it does not have a single scientific mineral name; rather, it's a piece of a rock which is a combination of minerals. If it were granite, its main mineral composition would be quartz (SiO2), feldspar (e.g., KAlSi3O8 - orthoclase, (Na,Ca)(Al,Si)4O8 - plagioclase), and mica (e.g., KAl2(AlSi3O10)(OH)2 - muscovite or K(Mg,Fe)3AlSi3O10(OH)2 - biotite), among others.
Mineral, possibly rock fragment containing a mineral
Granitic Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Kyanite (in Schist Matrix)
Kyanite (Al2SiO5)
metamorphic
Anthracite Coal
Anthracite (Carbon based)
metamorphic
River Cobble (Quartzite or Gneiss)
Metamorphic crystalline rock (predominantly SiO2 based)
metamorphic
Milky quartz (rough quartz)
Quartz, silicon dioxide (SiO₂)
mineral
Colorless Quartz (Rhinestone)
Silicon Dioxide (SiO2)
mineral
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals, Mg3Si2O5(OH)4)
metamorphic
Gneiss (River Cobble)
Gneiss
metamorphic
Milky quartz
Quartz (SiO₂)
mineral
Shungite
Non-crystalline carbon (allotrope of carbon)
metamorphic
Ruby / Pink Sapphire
Corundum (Al2O3 with Chromium impurities)
gemstone
Graphite
Graphite (C)
mineral
Pink Granite
Phaneritic Granitoid
igneous
Sapphire
Corundum (Al2O3)
mineral
Quartz with Iron Staining
SiO2 with Fe oxide impurities
mineral
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Quartzite with Mica / Gneiss Pebble
Metamorphic Rock (Quartz-Feldspar-Mica aggregate)
metamorphic
Blue Sapphire
Corundum (Al2O3)
mineral
Rough Gemstone Grains (Mixed Sapphires and Quartz)
Corundum (Al2O3) and Quartz (SiO2)
mineral
Quartzite Pebble
Quartzite (SiO2 based)
metamorphic
Quartz / Quartzite
Silicon Dioxide (SiO2)
metamorphic
Graphite
Graphite (Carbon, C)
mineral
Graphite
Graphite (Carbon, C)
mineral
Muscovite
KAl2(AlSi3O10)(OH)2
mineral
Faceted clear gemstone, likely glass or cubic zirconia
Undetermined; could be synthetic cubic zirconia (ZrO₂) or cut glass (silica-based)
gemstone
Green Kyanite
Kyanite (Al2SiO5)
mineral
Labradorite
Labradorite ((Ca, Na)(Al, Si)4O8)
mineral
Gneiss
Gneiss
metamorphic
Milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Gravel (Crushed Stone Aggregates)
Mixed Siliciclastic / Carbonate Aggregate
sedimentary
Kyanite
Kyanite (Al2SiO5)
mineral
Lapis Lazuli
Na8(Al6Si6O24)S2 (Lazurite is the primary constituent mineral)
metamorphic
Tumbled milky quartz
Quartz, silicon dioxide (SiO₂)
mineral
Green Aventurine
Aventurine Quartz (SiO2 with Fuchsite inclusions)
mineral
Kaolinite (Kaolin)
Kaolinite (Al2Si2O5(OH)4)
mineral
Anthracite Coal
Anthracite (Carbon-based metamorphic rock)
metamorphic
Blue Kyanite
Kyanite (Al2SiO5)
mineral