Weathered banded sandstone pebble
Quartz-rich sandstone (predominantly SiO₂)
sedimentary
Category
Man Made Material
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Chert (variations include Flint/Jasper)
Cryptocrystalline Silicon Dioxide (SiO2)
sedimentary
Cherry Creek Jasper (also known as Red Creek Jasper or Cherry Creek Agate)
Jasper, microcrystalline quartz (SiO₂)
Sedimentary Rock
Chalk / Sedimentary Limestone
Calcium Carbonate (CaCO3) - Biogenic Sedimentary Rock
sedimentary
Rose Quartz
Silicon Dioxide with trace elements (SiO2 + Ti, Fe, or Mn)
mineral
Polished leopard-skin jasper
Jasper, a microcrystalline quartz variety (SiO₂), with iron-oxide and other mineral impurities
sedimentary
Sandstone (specifically Red Sandstone)
Arenite (SiO2 with Iron Oxide)
sedimentary
Greenstone, likely serpentinite
Serpentinite; predominantly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with chlorite, talc, magnetite, or antigorite
metamorphic
Serpentine (likely serpentinized ultramafic rock)
Serpentine-group minerals, chiefly antigorite, lizardite, or chrysotile; commonly derived from peridotite
metamorphic
Serpentinite
Serpentinite (composed mainly of Group: Serpentine; (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)
metamorphic
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)
Igneous
Likely basalt or vesicular volcanic rock
Basalt, possibly scoriaceous basalt; exact identification is uncertain from the photograph
igneous
Granite
Granite (felsic intrusive igneous rock)
igneous
Red Jasper
Silicon dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Granite
Granite (composed primarily of Quartz, Feldspar, and Mica/Amphibole)
igneous
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Granite
Course-grained intrusive igneous rock
igneous
Diabase (also known as Dolerite)
Diabase / Dolerite
igneous
Limestone (specifically Travertine or Tufa)
Calcium Carbonate (CaCO3)
sedimentary
Sandstone (with potential mineral inclusions)
Clastic sedimentary rock (primarily Quartz, SiO2)
sedimentary
Granite River Rock
Phaneritic Felsic Igneous Rock (Granite)
igneous
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Serpentinite
Serpentinite (composed primarily of Serpentine group minerals, (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)
metamorphic
Quartzite Pebbles
Quartzite (SiO2)
metamorphic
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Diamond
Carbon (C)
gemstone
Turquoise
Turquoise (Hydrated copper aluminum phosphate, CuAl6(PO4)4(OH)8·4H2O)
Mineral
Clear quartz sphere or polished quartz cabochon (tentative)
Quartz, silicon dioxide (SiO₂); appearance may also be consistent with ordinary glass, which cannot be ruled out from the image alone
gemstone
Petrified Wood
Silicified Wood (SiO2)
fossil
Silver-bearing galena ore
Galena (PbS), likely in a quartz/carbonate-rich matrix with possible sulfide minerals
mineral
Crackle Quartz (Dyed)
SiO2 (Silicon Dioxide) - Treated
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Iron-rich quartzite or ferruginous metamorphic rock
Quartzite, predominantly SiO₂, stained by iron oxides (hematite/goethite)
metamorphic
Chert (Yellow Jasper/Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Diamond
Carbon (C)
Mineral
Tree Agate (or Moss Agate)
Dendritic Agate (Silicon Dioxide - SiO2)
mineral
Chert (with Chalky Cortex)
Silicon Dioxide (SiO2)
sedimentary
Moss Agate / Carnelian Agate
Silicon Dioxide (SiO2) with iron and manganese inclusions
mineral
Likely obsidian (possibly tektite or slag glass)
Volcanic glass; primarily SiO₂, noncrystalline
igneous
Native American Hammerstone / Pitted Stone
Modified lithic artifact (often quartzite, basalt, or granite)
artifact / sedimentary or igneous rock
Quartzite
Quartzite (Metamorphosed Quartz Sandstone)
metamorphic