Chert Nodules in Limestone
Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)
sedimentary
Category
Sedimentary Or Igneous (Host Environment)
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Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Chalcedony (Agate Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Wishing Stone (Quartz-veined Metamorphic/Sedimentary Rock)
Quartz Vein in Greywacke/Slate (SiO2 in host rock)
metamorphic
Worn River Pebble with Fossil Indentation
Sedimentary Rock with Fossil Infill
sedimentary
Weathered quartz-rich metamorphic rock, likely gneiss or schist
Quartz–feldspar–mica gneiss/schist (tentative; image resolution limits certainty)
metamorphic
Gneiss with Quartz Vein
Gneiss containing Quartz (SiO2) filler
metamorphic
Turquoise
Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
mineral
Chalcedony (Agate / Chert)
Silicon Dioxide (SiO2)
mineral
Pink Chalcedony
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Likely garnet-bearing schist or gneiss
Mica schist/gneiss containing quartz, feldspar, mica, and probable almandine garnet
metamorphic
Quartz on Matrix
Silicon Dioxide (SiO2)
mineral
Purple Chalcedony
Silicon Dioxide (SiO2)
mineral
Likely weathered quartz-rich rock fragment
Uncertain; possibly quartz-bearing granitic or metamorphic material (SiO₂-dominant)
mineral
Tourmaline-rich schist (likely black tourmaline)
Schist containing schorl, Fe-rich NaFe3Al6(BO3)3Si6O18(OH)4
metamorphic
Chert Nodule or Concretion
Microcrystalline Quartz / Sedimentary Nodule
sedimentary
Druzy Quartz on Matrix
Silicon Dioxide (SiO2)
mineral
Geode
Silicon Dioxide (Quartz/Chalcedony) in carbonate or volcanic host rock
sedimentary
Quartz Crystal (Geode Fragment)
Silicon Dioxide (SiO2)
mineral
Biotite in Host Matrix
Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)
mineral
Milky Quartz with Garnet/Hematite and Basalt
Silicon Dioxide (SiO2) with Almandine (Fe3Al2Si3O12) and Basalt
mineral
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
mineral
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
mineral
Chalcedony on Matrix
Silicon Dioxide (SiO2)
mineral
Fossiliferous Sedimentary Rock
Sedimentary Rock with Invertebrate Fossil Imprint
fossil
Wishing Stone (Basalt with Quartz Vein)
Basalt containing a microcrystalline quartz (SiO2) or calcite vein
igneous
Mixed rough mineral specimens, likely quartz-bearing rocks
Probable quartz (SiO₂), with possible feldspar, iron oxides, and altered host rock
mineral
Weathered brown stone, possibly basalt or iron-rich sedimentary rock
Indeterminate from photograph; likely fine-grained mafic rock (basalt) or ferruginous sandstone
igneous
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2
mineral
Weathered sandstone
Quartz-rich clastic sandstone, chiefly SiO₂ with minor feldspar, lithic grains, and iron-oxide/clay cement
sedimentary
Turquoise
Hydrated phosphate of copper and aluminium: CuAl6(PO4)4(OH)8·4H2O
mineral
Pyrite-bearing rock (likely pyrite-rich shale or matrix specimen)
Pyrite (FeS₂) in a fine-grained host rock; host is uncertain from the image
sedimentary
Mica-rich schist (probable)
Mica schist, composed mainly of mica minerals with quartz and possibly feldspar
metamorphic
Veined Sandstone with Calcite Veins
Sedimentary sandstone with hydrothermal/mineral veins
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Small rounded pebble, likely quartz-rich river stone
Indeterminate; likely quartz/chert-bearing lithic clast
sedimentary
Milky Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Quartz (specifically Milky or Iron-stained Quartz)
Silicon Dioxide (SiO2)
mineral
Milky calcite
Calcite (calcium carbonate, CaCO₃)
mineral
Quartz Pebble (Iron-stained Chalcedony / Chert)
Silicon Dioxide (SiO2)
sedimentary