Pebble
Lithified rock fragment / Sedimentary clast
sedimentary
Category
Mineral Based Composite
Browse mineral based composite specimens identified by the Rock Identifier community.
Learn about Mineral Based Composite in the encyclopedia
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Sandstone
Arenite (SiO2 primarily)
sedimentary
Weathered dark mineral/rock fragment
Indeterminate; possibly iron-rich basalt, slag, or a sulfide-bearing mineral
mineral
Sandstone (lithic/arkosic)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Dalmatian Jasper
Microcrystalline quartz feldspar composite with arfvedsonite or black tourmaline
igneous
Pink granite
Coarse-grained felsic intrusive rock, chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende
igneous
Red jasper / red chert
Microcrystalline quartz (chalcedony), SiO₂, colored chiefly by iron oxides
sedimentary
Tumbled quartz-rich stone, possibly granite or sandstone
Uncertain from image; likely quartz (SiO₂) with iron-oxide and feldspar impurities
igneous
Chert (Cream Variety)
Microcrystalline silica (SiO2)
sedimentary
Sandstone (Ferruginous)
Clastic sedimentary rock (primarily SiO2 with Fe2O3)
sedimentary
Sandstone (Red Sandstone)
Arenite (SiO2 based with Fe2O3 staining)
sedimentary
Beryllonite
Beryllonite (NaBePO4)
mineral
Bumblebee Jasper
Calcite with Arsenic and Sulfur inclusions
sedimentary
Milky Quartz
Crystalline Silicon Dioxide (SiO2)
mineral
Polished/tumbled stone, likely serpentine or agate
Probable serpentine-group mineral (antigorite/lizardite), possibly a green jasper or agate; image is insufficient for certainty
mineral
Malachite cabochon or polished bead
Malachite, Cu₂CO₃(OH)₂
mineral
Sandstone
Sandstone (Silicon dioxide, SiO2 based)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Conglomerate
Sedimentary Conglomerate with Basaltic Clast
sedimentary
Quartz-rich gravel fragment
Quartz (silicon dioxide, SiO₂), possibly with feldspar or carbonate inclusions
mineral
Sandstone (Arkose/Quartzose)
Arenite (SiO2 based clastic rock)
sedimentary
Bivalve Fossil (Clam Stone)
Phylum Mollusca, Class Bivalvia
fossil
Turquoise cabochon jewelry
Turquoise, hydrated copper aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O
gemstone
Mixed Tumbled Gemstones (Agate, Aventurine, Pyrite, etc.)
Multiple (principally Silicon Dioxide SiO2 and Iron Disulfide FeS2)
mineral
Unakite
Altered granite (Epidote, Orthoclase Feldspar, and Quartz)
metamorphic
Sandstone
Arenite (SiO2 based with various cements)
sedimentary
Sandstone (likely Graywacke or Arkose variant)
Clastic Sedimentary Rock (SiO2 based)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2 based clastic rock)
sedimentary
Gold
Gold (Native Element); Au
mineral
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
igneous
Concretion
Calcareous or ferruginous concretion
sedimentary
Que Sera Stone (Llanite with Feldspar and Quartz)
Rhyolite with blue quartz and pink orthoclase (Llanite-type quartz porphyry)
igneous
Shungite
Shungite (carbon-rich Precambrian rock)
mineral
Pearl
Calcium Carbonate (CaCO3) + Conchiolin
mineral
Decorative orb of likely sodalite-bearing rock or dyed stone
Most consistent with sodalite-rich nepheline syenite or a blue-and-white composite; exact identification requires testing
mineral
Black tourmaline pendant
Schorl, a sodium–iron tourmaline; approximate formula NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
mineral
Ruby / Pink Sapphire
Corundum (Al2O3 with Chromium impurities)
gemstone
Porphyry (Flower Stone)
Porphyritic Basalt or Andesite
igneous
Polished turquoise-bearing rock
Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O, likely in a brown host rock or matrix
mineral
Geode or Concretion
Silica-based Concretion / Quartz Geode
sedimentary
Aquamarine
Beryl (Be3Al2Si6O18)
gemstone
Green Tourmaline (Verdelite)
Complex sodium iron aluminum borosilicate (Na(Mg,Fe,Li,Al,Mn)3Al6(BO3)3Si6O18(OH)4)
gemstone