Pegmatite with quartz, feldspar, mica, and tourmaline
Granitic pegmatite; chiefly quartz (SiO₂), feldspar, muscovite, and black schorl tourmaline (NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
igneous
Category
Anthropogenic (Man Made Material)
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Chalcedony (gray-white agate)
Microcrystalline quartz, SiO₂
mineral
Quartz-rich metamorphic rock (likely mica schist or gneiss)
Quartz–feldspar–mica assemblage; probable biotite schist/gneiss
metamorphic
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (and Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Carved Gemstone Mushroom
Quartz / Feldspar composite (Carved lapidary art)
gemstone
Fossilized Coral
Rugose coral / Tabulate coral fossil in limestone matrix
fossil
Tumbled brown jasper
Microcrystalline quartz/chalcedony (SiO₂), commonly iron-oxide stained
sedimentary
Crushed Stone (Gravel/Aggregates)
Crushed rock aggregate (varied composition including Granite, Limestone, and Quartz)
sedimentary and igneous (mixed)
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (SiO2 primarily)
sedimentary
Schist
Schist
metamorphic
Tumbled chalcedony (likely milky quartz)
Chalcedony, cryptocrystalline SiO₂; possibly quartz-rich chert
mineral
Granite River Cobble
Phaneritic Felsic Igneous Rock (Granite)
igneous
Quartzite
Quartzite (principally SiO2)
metamorphic
Yellow Quartzite Pebble
Quartzite (SiO2)
metamorphic
Plume Agate or Moss Agate
Agate (SiO2)
mineral
Likely tumbled jasper or iron-rich chert
Microcrystalline quartz (SiO₂), potentially hematite/goethite-bearing
mineral
Small vesicular volcanic rock, likely scoria
Scoria; predominantly basaltic to andesitic volcanic rock
igneous
Rounded brown-gray stone, possibly weathered conglomerate or sandstone
Indeterminate clastic sedimentary rock; likely poorly cemented sandstone/conglomerate
sedimentary
Dalmatian Stone and Lapis Lazuli
Dalmatian Stone (peralkaline rock) with Lapis Lazuli (metamorphic rock)
igneous
Fossiliferous limestone, possibly containing a brachiopod or bivalve fossil
Calcite-rich limestone (CaCO₃), with an apparent shell impression or shell fragment
fossil
Rhodonite
Rhodonite, manganese inosilicate — MnSiO₃; the specimen may include quartz, feldspar, and black manganese-oxide minerals in the matrix
mineral
Sandstone
Arenite (composed mainly of SiO2)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz pebble
Silicon dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Crystal
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Kyanite
Al2SiO5
mineral
Quartz
Silicon dioxide (SiO2)
Mineral
Quartz, Sandstone, and Siltstone specimens
Silicon Dioxide (SiO2) and Clastic Sedimentary Rocks
mineral and sedimentary
Jasper
Silicon Dioxide (Microcrystalline Quartz), SiO2
sedimentary
Limestone (River Pebble)
Calcium Carbonate (CaCO3)
sedimentary
Granite
Intrusive igneous rock composed mainly of quartz, alkali feldspar, and plagioclase
igneous
Chondrite Meteorite
L or H Ordinary Chondrite
meteorite
Sandstone (with Moss/Lichen Growth)
Sandstone (Quartz Arenite / Lithic Arenite)
sedimentary