Quartz
Silicon dioxide (SiO2)
mineral
Category
Metamorphic Or Sedimentary Depending On Local Grade
Browse metamorphic or sedimentary depending on local grade specimens identified by the Rock Identifier community.
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Quartz Boulder
Silicon Dioxide (SiO2)
mineral
Kyanite
Kyanite (Al2SiO5)
mineral
Chert Arrowhead (Lithic Artifact)
Chert (Cryptocrystalline Quartz, SiO2)
sedimentary
Anthracite Coal
Anthracite (Carbon rank grade)
sedimentary
Muscovite schist
Mica schist, chiefly muscovite mica (KAl₂(AlSi₃O₁₀)(OH)₂) with quartz and feldspar
metamorphic
Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Banded jasper (polished/tumbled)
Microcrystalline quartz (SiO₂), commonly iron-oxide– and clay-rich chert
sedimentary
Gneiss
Gneiss
metamorphic
Tumbled cream-colored pebble
Likely quartz-rich sandstone or limestone; exact identification requires testing
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Hornblende-bearing metamorphic rock (likely amphibolite)
Amphibolite, chiefly hornblende amphibole and plagioclase feldspar
metamorphic
Banded Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Gneiss
Gneiss (High-Grade Metamorphic Rock)
metamorphic
Granitic Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Granite Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Chlorite-rich metamorphic rock, likely greenschist
Greenschist; commonly composed of chlorite, actinolite, epidote, albite, and quartz
metamorphic
Magnetite (Lodestone)
Magnetite (Fe3O4)
mineral
Serpentinite-bearing quartz vein rock
Serpentinite (antigorite/lizardite) with milky quartz; possible chlorite or epidote alteration
metamorphic
Nephrite Jade
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Metamorphic
Tanzanite
Zoisite (Ca2Al3(SiO4)(Si2O7)O(OH))
gemstone
Gneiss
High-grade regional metamorphic rock (Foliated)
metamorphic
Biotite Schist
Biotite Schist (K(Mg,Fe)3AlSi3O10(OH,F)2)
metamorphic
Banded gneiss
Gneiss, commonly quartz–feldspar–biotite gneiss
metamorphic
Weathered gray metamorphic rock, likely schist or gneiss
Micaceous quartz-feldspar schist/gneiss; exact identification requires a fresh surface and testing
metamorphic
Anthracite Coal
Anthracite coal (High-rank coal)
sedimentary
Feldspar (Potassium Feldspar / Orthoclase)
KAlSi3O8 (Potassium Aluminum Silicate)
mineral
Potassium Feldspar
Orthoclase (KAlSi3O8)
mineral
Black Tourmaline
Schorl (Sodium Iron Aluminum Borosilicate Hydroxide); NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)
mineral
Granitic Pegmatite Intrusion in Host Rock
Pegmatite dike in amphibolite or schist
igneous and metamorphic
Granite Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Blue Kyanite
Kyanite (Al2SiO5)
mineral
Rounded sandstone pebble
Quartz-rich sandstone (likely litharenite or subarkose)
sedimentary
Quartz Geode (Cracked Open Fragment)
Silicon Dioxide (SiO2)
mineral
Rainbow Moonstone (White Labradorite)
White Labradorite (Feldspar variety, (Na,Ca)(Al,Si)4O8)
mineral
Yellow Sapphire
Corundum (Al2O3)
mineral
Gold-bearing dark rock, possibly magnetite with iron-oxide staining
Likely magnetite (Fe₃O₄) with limonite/goethite; metallic patches may be gold or weathered sulfide, unconfirmed
mineral
Glacial Erratic (Graywacke/Sandstone)
Clastic Sedimentary Rock (Lithic Sandstone)
sedimentary
Fossiliferous Limestone with Fossil Fragment
Fossiliferous Limestone (CaCO3 with organic remains)
fossil
Weathered granitic boulder
Granite, typically composed of quartz, feldspar, and mica
igneous
Amber-set ring
Amber (fossilized plant resin; organic mineraloid), set in a metal ring
gemstone
Likely gneiss pebble
Foliated quartz–feldspar gneiss, with dark biotite or amphibole
metamorphic