Vesicular Basalt / Scoria pebble
Extrusive igneous rock with amygdaloidal infilling
igneous
Category
Not A Natural Rock (Man Made Composite)
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Chert (Flint / Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Marble
Metamorphic Limestone (CaCO3)
metamorphic
Dyed Quartz Geode
Silicon Dioxide (SiO2) with artificial purple dye
mineral
Sandstone
Arenite (primarily Quartz Arenite)
sedimentary
Sandstone
Sandstone (composed predominantly of Quartz, SiO2, with Feldspar and Clay minerals)
sedimentary
Sandstone
Arenite (SiO2 primarily)
sedimentary
Diamond
Carbon (C)
gemstone
Pearl
Aragonite (CaCO3 with conchiolin)
mineral
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Tiger Iron
Tiger Iron (Hematite, Red Jasper, and Chert/Tiger's Eye composite)
metamorphic
Polished blue stone, likely sodalite or dyed agate
Sodalite: Na₈(Al₆Si₆O₂₄)Cl₂; exact identification requires testing
mineral
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
man-made alloy (metallic)
Banded malachite cabochon
Malachite, Cu₂CO₃(OH)₂; the dark bands may be manganese-oxide or other sulfide-rich matrix, and could also indicate a composite or treated specimen
mineral
Sandstone (likely Quartzose)
Clastic sedimentary rock (SiO2 primary)
sedimentary
Chert (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
sedimentary
Granite
Phaneritic Felsic Igneous Rock
igneous
Basalt
Basalt (Mafic volcanic rock)
igneous
Diorite
Intermediate plutonic igneous rock
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Sandstone (Quartzose Sandstone)
Arenite (composed primarily of SiO2)
sedimentary
Titanium Aura Quartz
Titanium-coated Silicon Dioxide (SiO2)
mineral (man-enhanced)
Vesicular Basalt
Extrusive mafic igneous rock
igneous
Sandstone
Sedimentary Rock (Quartz Sandstone)
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Flint / Chert
Microcrystalline Quartz (SiO2)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary
Sandstone
Arenite (predominantly SiO2)
sedimentary
Red Swirl Beads (Likely Resin or Glass, simulating Red Jasper or Agate)
N/A (for the beads as pictured); Red Jasper: SiO2 (Chert variety); Red Agate: SiO2 (Chalcedony variety)
Organic (if resin) or Synthetic (if glass); simulating Sedimentary or Metamorphic (for natural stones)
Limpets Shell / Fossil Specimen
Patellogastropoda (Class)
fossil
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Geode with Quartz and possibly Jasper/Hematite
Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides
Mineral/Sedimentary Geode
Beach Pebble (Chalcedony / Chert)
Silicon Dioxide (SiO2)
mineral
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Red Painted Rock
Artificial Coated Lithic Fragment
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
sedimentary
Sandstone
Arenite
sedimentary
Polished blue calcite sphere (tentative identification)
Calcite, CaCO₃; blue color generally results from trace impurities or inclusions
mineral
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Quartzite
Quartzite (Metamorphic Quartz Sandstone)
metamorphic