Weathered granite fragment
Granite, primarily quartz, feldspar, and mica
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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White Sapphire
Corundum (Al2O3)
mineral
Quartz-bearing pegmatitic rock, likely granite/pegmatite
Feldspar–quartz pegmatite; chiefly K-feldspar, plagioclase, quartz, and possible mica
igneous
Serpentinite (often called Jade or Nephrite substitute)
Serpentinite (composed primarily of Antigorite, Lizardite, or Chrysotile)
metamorphic
Coarse-grained granite or granitic pegmatite fragment
Granite; primarily quartz, feldspar, and mica
igneous
Sandstone
Arenite (SiO2 based)
sedimentary
Sandstone (Banded)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Tumbled greenstone, likely serpentine or altered basalt
Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; possibly chlorite/epidote-bearing mafic rock
metamorphic
Unidentified weathered mineral/rock fragment
Indeterminate; likely a weathered iron-rich silicate or sulfide-bearing specimen
mineral
Boulder Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Turquoise ring (likely stabilized or imitation turquoise)
Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; exact material is uncertain from the image
gemstone
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)
sedimentary
Colorless Gemstone (possibly Diamond or Cubic Zirconia)
C (Diamond) or ZrO2 (Cubic Zirconia)
gemstone
Sandstone (Ferruginous)
Arenite (Siliclastic Sedimentary Rock)
sedimentary
Sandstone
Sandstone (SiO2-dominated clastic rock)
sedimentary
Tumbled amber-colored agate or chalcedony
Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/agate
mineral
Granite fragment
Granite; mainly quartz (SiO₂), feldspar, and mica
igneous
Red jasper
Jasper, an opaque microcrystalline quartz variety (SiO₂), colored mainly by iron oxides
mineral
Porphyritic Basalt or Porphyritic Andesite
Porphyritic volcanic rock
igneous
Sandstone
Sandstone (SiO2 with iron oxides and clay)
sedimentary
Sandstone
Sandstone (SiO2 rich)
sedimentary
Sandstone
Arenite (SiO2 primarily)
sedimentary
Asphalt Concrete (Bituminous Conglomerate)
Anthropogenic Bituminous Conglomerate
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Sandstone
Arenite (Siliclastic sedimentary rock)
sedimentary
Sandstone
Quartzose Sandstone (Sedimentary Rock)
sedimentary
Green glassy slag (often sold as “sea glass” or “green obsidian”)
Industrial vitreous slag; primarily amorphous silicate glass, composition variable
mineral
Emerald
Beryl (Be3Al2(SiO3)6)
gemstone
Cubic Zirconia (Simulated Diamond)
Zirconium Dioxide (ZrO2)
mineral (synthetic)
Red Sandstone
Sandstone (Quartz Arenite / Arkose with Hematite cement)
sedimentary
Poppy Jasper
Microcrystalline Quartz (SiO2) with mineral inclusions
sedimentary
Sandstone
Arenite (predominantly SiO2)
sedimentary
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Milky quartz with dark mineral veins
Quartz, silicon dioxide (SiO₂), likely massive vein quartz; dark veins may be chlorite, mica, iron/manganese oxides, or a sulfide mineral
mineral
Ocean Jasper or Orbicular Jasper
SiO2
mineral
Sandstone
Arenite (SiO2 predominantly)
sedimentary
Sandstone
Arenite (primarily Quartz and Feldspar)
sedimentary
Tumbled blue-gray stone, likely basalt or slate
Probable fine-grained basalt; exact identification is uncertain from the photograph
igneous
Fossil bivalve or brachiopod in sedimentary rock
Unidentified fossil shell impression; likely a ribbed bivalve or brachiopod preserved in shale/siltstone
fossil
Opalite
Synthetic Fluorescent Glass (SiO2 + impurities)
mineraloid (synthetic)
Brecciated quartz vein rock
Quartz (SiO₂), with iron-oxide staining and likely feldspar/carbonate gangue
mineral
Sandstone
Arenite (SiO2 primarily)
sedimentary