Bivalve Fossil (Shell Fragment)
Class Bivalvia (Calcium Carbonate - CaCO3)
sedimentary
Category
Not A Rock (Man Made Polymer)
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Likely slate
Slate, a fine-grained metamorphic rock composed mainly of mica-group minerals and quartz
metamorphic
Granite
Felsic intrusive igneous rock
igneous
Black-and-white agate geode pendant
Agate (microcrystalline quartz, SiO₂), likely a hollow geode slice with chalcedony and drusy quartz
mineral
Chert Arrowhead
Cryptocrystalline Quartz (SiO2)
sedimentary
Amber
Succinite (Fossilized Resin)
mineral
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Sandstone
Sandstone (composed predominantly of Quartz, SiO2, with Feldspar and Clay minerals)
sedimentary
Native Silver
Silver (elemental Ag)
mineral
Granite
Phaneritic Felsic Intrusive Igneous Rock
igneous
Chert (often called Flint)
Chert (Microcrystalline or cryptocrystalline Silica, SiO2)
sedimentary
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
man-made alloy (metallic)
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
sedimentary
Sandstone
Clastic sedimentary rock (Quartz arenite/Arkose)
sedimentary
Coquina
Biogenic Limestone (CaCO3)
sedimentary
Tumbled quartz-rich pebble
Microcrystalline quartz (SiO₂), possibly milky quartz or quartzite
mineral
Bauxite
Alumina ore (Mixture of Gibbsite, Boehmite, and Diaspore)
sedimentary
Granite
Granite (Phaneritic Quartz-Feldspar intrusive rock)
Igneous
Chert (Flint / Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Marble
Metamorphic Limestone (CaCO3)
metamorphic
Unakite
Altered Granite (Epidotized Granite)
metamorphic
Bauxite (Pisolitic Bauxite)
Bauxite (mixture of Hydrous Aluminum Oxides)
sedimentary
Lapis Lazuli
Lapis Lazuli (Primary mineral: Lazurite (Na,Ca)8(AlSiO4)6(SO4,S,Cl)2)
metamorphic
Note regarding baguette production (not a rock)
Digital text image - Somali language
not a rock
Fulgarite
Fulgurite (Lechatelierite / Vitrified Sand)
igneous
Turquoise
Turquoise, CuAl6(PO4)4(OH)8·4H2O
mineral
Pink Granite (Alkali-feldspar Granite)
Felsic intrusive igneous rock (composition: KAlSi3O8, SiO2, NaAlSi3O8)
igneous
Lapis Lazuli
Lapis Lazuli (a rock, not a single mineral; primary mineral is Lazurite (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2
Metamorphic rock
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Granite
Phaneritic Felsic Igneous Rock
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Concrete or asphalt-like aggregate surface with a dark fragment
Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock
sedimentary
Polished blue calcite sphere (tentative identification)
Calcite, CaCO₃; blue color generally results from trace impurities or inclusions
mineral
Rounded quartz pebble
Quartz (silicon dioxide, SiO₂)
mineral
Polished dark gray stone, likely basalt or fine-grained andesite
Basalt/andesite; primarily plagioclase feldspar, pyroxene, and possibly olivine or magnetite
igneous
Goldstone (Synthetic Aventurescence Glass)
Cuprous Aventurescent Glass (Silicon Dioxide with Copper inclusions)
mineraloid / man-made material
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
sedimentary
Likely blue glass or synthetic gemstone jewelry
Uncertain; possibly synthetic spinel, cubic zirconia, or blue glass
gemstone
Limestone
Sedimentary Rock (Primarily CaCO3)
sedimentary
Beach Pebble (Chalcedony / Chert)
Silicon Dioxide (SiO2)
mineral
Chert (Flint)
Microcrystalline quartz (SiO2)
sedimentary