Quartz
Silicon Dioxide (SiO₂)
Mineral
Category
Sedimentary (Processed Mineral Product)
Browse sedimentary (processed mineral product) specimens identified by the Rock Identifier community.
Learn about Sedimentary (Processed Mineral Product) in the encyclopedia
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Pyrite nodule (probable iron sulfide concretion)
Pyrite, FeS₂, likely weathered within a sedimentary concretion
mineral
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Raw Pink Salt (Himalayan Salt)
Halite (NaCl with trace minerals)
mineral
Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Yellow calcite crystal cluster with calcite fragment
Calcite, calcium carbonate (CaCO₃)
mineral
Prehnite
Ca2Al(AlSi3O10)(OH)2 (Calcium Aluminum Silicate hydroxide)
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Blue Kyanite
Kyanite (Al2SiO5)
mineral
Tumbled dark stone, likely basalt or basaltic rock
Fine-grained mafic volcanic rock; commonly basalt, composed chiefly of plagioclase and pyroxene with possible olivine and iron oxides
igneous
Yellow Aventurine (Yellow Quartz)
Silicon Dioxide (SiO2) with inclusions of Muscovite or Mica
Mineral (variant of Quartz)
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Polished agate bracelet (likely gray chalcedony)
Microcrystalline quartz, SiO₂; chalcedony/agate variety
gemstone
Olivine (peridot) crystal
Olivine group, (Mg,Fe)₂SiO₄; likely forsterite–fayalite solid solution
mineral
Likely blue-green kyanite crystal
Kyanite, Al₂SiO₅
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Chert (specifically Yellow/Common Opal or Jasper mixture)
Silicon Dioxide (SiO2)
sedimentary
Mixed Mineral and Crystal Assortment
Various silicate and oxide minerals
mineral
Pyrite Ore
Iron Sulfide (FeS2)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Likely milky quartz pebble
Quartz (SiO₂), crystalline silica
mineral
Serpentinite pebble
Serpentinite, composed chiefly of serpentine-group minerals (lizardite, chrysotile, antigorite), with possible magnetite and chlorite
metamorphic
Gold-bearing quartz vein fragment (probable placer gold specimen)
Quartz (SiO₂) with probable native gold (Au) and iron-oxide staining
mineral
Weathered granite or granitic gneiss
Granite: quartz + feldspar + mica; possible gneissic variant
igneous
Weathered dark volcanic rock, likely basalt
Basalt (plagioclase–pyroxene ± olivine), tentative identification
igneous
Greenstone (likely serpentinite or greenstone pebble)
Serpentinite-rich ultramafic rock; commonly dominated by serpentine-group minerals, with possible chlorite, actinolite, or magnetite
metamorphic
Uncertain polymict breccia or altered volcanic rock
Likely hydrothermally altered volcanic breccia; exact mineral identification requires testing
igneous
Shark Tooth Fossil
Chondrichthyes tooth
fossil
Weathered basalt or volcanic scoria fragment
Basaltic volcanic rock; chiefly plagioclase, pyroxene, and iron-rich oxides
igneous
Turquoise (rough, likely stabilized or treated)
Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O
mineral
Dragon Vein Agate (Dyed/Treated)
Agate (SiO2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Tumbled howlite (likely)
Howlite, Ca₂B₅SiO₉(OH)₅
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Greenstone or Epidote-rich Metamorphic Rock
Chlorite/Epidote Schist or Greenstone
metamorphic
Tumbled granite (likely granite or granitic gneiss)
Granite; chiefly quartz (SiO₂), feldspar, and mica, with possible alteration minerals
igneous
Polished amethyst-bearing quartz
Quartz, SiO₂; purple coloration from trace iron and irradiation, likely in an amethyst/quartz matrix
mineral
Limonite Concretion
FeO(OH)·nH2O (Hydrated Iron Oxide)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Fossil Shark Tooth
Chondrichthyes (tooth)
fossil
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Porous volcanic rock (likely scoria)
Scoria, vesicular basaltic to andesitic volcanic rock
igneous