Weathered granitic rock, likely granodiorite
Granodiorite: quartz, plagioclase feldspar, potassium feldspar, and biotite/hornblende
igneous
Category
Synthetic Material (Not A Rock Or Mineral)
Browse synthetic material (not a rock or mineral) specimens identified by the Rock Identifier community.
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Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Rounded basalt pebble
Basalt, aphanitic mafic volcanic rock; primarily plagioclase and pyroxene with possible olivine
igneous
Dyed or treated turquoise-like tumbled stone
Likely turquoise (CuAl₆(PO₄)₄(OH)₈·4H₂O), though blue-green magnesite or howlite imitation is possible
mineral
Red Sandstone
Arenite (primarily SiO2 with Fe2O3)
sedimentary
Jasper River Stone
Silicon Dioxide with Iron Oxide impurities (SiO2 + Fe2O3)
sedimentary
Sandstone (Red/Brown Variety)
Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)
sedimentary
Sandstone (Banded)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide staining)
sedimentary
Banded Agate (specifically Carnelian Agate)
Silicon dioxide (SiO2) - Chalcedony variety
mineral
Sandstone (Ferruginous)
Ferruginous Sandstone (SiO2 with Fe2O3)
sedimentary
Slate
Slate (foliated metamorphic rock)
metamorphic
Sandstone
Arenite (primarily SiO2 - Silicon Dioxide)
sedimentary
Granitic gneiss (weathered, rounded cobble)
Foliated granitoid; primarily quartz, feldspar, and mica (composition commonly approximates granite)
metamorphic
Granite
Phaneritic Igneous Rock (Granite)
igneous
Gneiss
Gneiss
metamorphic
Red Sandstone (Iron-rich Sandstone)
Clastic Sedimentary Rock - Quartz Arenite / Arkose with Hematite Cement
sedimentary
Sandstone (Quartz Sandstone)
Arenite (primarily SiO2)
sedimentary
Chert (Arrowhead Fragment)
Cryptocrystalline quartz (SiO2)
sedimentary
Synthetic Zinc/Polycarbonate Composite (Bey-specimen)
Zinc Alloy (Zamak 3) with Polycarbonate (C15H16O2)n Overlay
Anthropogenic Mineral Mimic
Tumbled-looking granite pebble
Granite, chiefly quartz–feldspar with biotite/amphibole
igneous
Feldspathic Gneiss (Granite Gneiss)
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Green-and-gold apatite-bearing rock, possibly epidote skarn
Apatite-group mineral, commonly fluorapatite (Ca₅(PO₄)₃F), with probable epidote and quartz; exact identification requires testing
mineral
Asphalt Concrete (Bituminous Pavement)
Aggregates in Bitumen Matrix
Technogenic / Anthropogenic Pavement Material
Slag
Ferrous Slag (Amorphous calcium-magnesium-aluminum silicates)
igneous (artificial/anthropogenic)
Quartz-rich rock, possibly milky quartz or quartzite
Quartz (silicon dioxide, SiO₂); if granular and foliated, likely quartzite
mineral
Polished granite pebble
Granite, commonly quartz–feldspar–mica aggregate
igneous
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Diorite
Diorite
igneous
Tumbled gneiss
Gneiss, chiefly quartz–feldspar with mica and dark ferromagnesian minerals
metamorphic
Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Vesicular basalt
Basalt, typically composed of plagioclase feldspar, pyroxene, and minor olivine or iron oxides
igneous
Polished brecciated jasper
Silicified breccia, chiefly microcrystalline quartz (SiO₂) with iron-oxide staining
mineral
Weathered granite pebble
Granite, chiefly quartz (SiO₂), feldspar, and mica/amphibole
igneous
Sandstone (specifically Cross-bedded Sandstone)
Arenite (composed primarily of SiO2)
sedimentary
Sandstone
Arenite (mostly Quartz-based)
sedimentary
Granite
Phaneritic Acidic Igneous Rock (Granite)
igneous
Sandstone
Arenite
sedimentary
Slate
Slate (Metamorphic Rock)
metamorphic
Schist with Quartz Veins
Schist with Quartz (SiO2)
metamorphic
Gravel / Small Pebble
Rock Fragment (Gravel)
sedimentary
Slate
Slate (Foliated Metamorphic Rock)
metamorphic
Tumbled gray-green metamorphic rock, likely serpentinite or chlorite schist
Serpentinite/chlorite-rich ultramafic metamorphic rock; commonly dominated by antigorite, lizardite, or chlorite with minor magnetite and talc
metamorphic