River Rock (Basalt/Greywacke pebbles)
Fluvial gravel primarily composed of Mafic Volcanic Rock (Basalt) or Lithic Sandstone (Greywacke)
igneous and sedimentary
Category
Sedimentary Or Igneous Fragment
Browse sedimentary or igneous fragment specimens identified by the Rock Identifier community.
Wishing Stone (Basalt/Greywacke with Quartz Vein)
Basalt or Siltstone with SiO2 (Quartz) hydrothermal intrusion
igneous/sedimentary
Muscovite Mica
Muscovite (Potassium Mica) KAl2(AlSi3O10)(OH)2
Mineral
Quartz (possibly milky quartz or quartz with inclusions)
SiO2 (Silicon Dioxide)
Mineral
Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)
Chalcedony (SiO₂)
Mineral (or mineraloid if microcrystalline)
Ruby in Zoisite
Ruby (α-Al2O3) embedded in Zoisite (Ca2Al3(SiO4)3(OH)) with some Hornblende
Metamorphic Rock (composed of multiple minerals)
Fluorite and Rose Quartz
Fluorite (CaF2), Rose Quartz (SiO2)
Mineral
Biotite Schist (likely)
Biotite Schist (rock), Biotite (mineral)
Metamorphic
Banded Gneiss (River Cobble)
Gneiss (a high-grade metamorphic rock)
metamorphic
Quartz (likely macrocrystalline variety)
Quartz (SiO₂)
Mineral
Jasper (specifically Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with impurities
sedimentary or igneous-associated mineral
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral, often found as detrital grains in sedimentary rocks
Banded Metamorphic Rock (likely Quartzite or Serpentinite/Soapstone)
Metamorphic Rock (possibly a banded Quartzite or a foliated Serpentinite/Talc Schist based on appearance, general term for such a rock is 'Banded Metamorphic Rock' or 'Gneiss' if pronounced banding of different minerals)
Metamorphic
Quartz Geode/Cluster
Quartz (SiO2)
mineral
Nephrite Jade
Nephrite (a variety of the mineral actinolite within the amphibole group); Chemical Formula: Ca2(Mg,Fe)5Si8O22(OH)2
Mineral
Quartzite
Quartzite (primarily SiO₂)
metamorphic
Epidote in Quartz
Quartz with Epidote inclusions (SiO2 with Ca2(Al,Fe)3(SiO4)3(OH) inclusions)
Mineral
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
Mineral
Apatite
Apatite group mineral (e.g., Fluorapatite - Ca5(PO4)3F, Chlorapatite - Ca5(PO4)3Cl, Hydroxylapatite - Ca5(PO4)3(OH))
mineral
Quartz (likely milky quartz or a stained variety)
Silicon Dioxide (SiO₂)
Mineral
Quartz Geode
Silicon Dioxide (SiO2) in a Geode body
sedimentary or igneous (host environment)
Quartz
Quartz (SiO₂)
Mineral
Quartz Vein in Host Rock (Breccia/Rhyolite)
Silicon Dioxide (SiO2) with matrix
Mineral in Igneous/Sedimentary host
Hematite
Hematite (Fe2O3)
Mineral
Pumice
Pumice (volcanic rock)
Igneous
Sapphire (Corundum variety)
Sapphire (Al₂O₃)
Mineral
Rutilated Quartz
SiO2 with TiO2 inclusions (Rutile)
Mineral
Quartz Pebble
Silicon Dioxide (SiO2)
Mineral / Sedimentary occurrence
Quartz
Silicon Dioxide (SiO2)
Mineral
Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Schist
N/A (a rock type, not a mineral formula)
metamorphic
Quartz (chalcedony variety) or Limestone with Quartz Veins
SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)
Mineral or Sedimentary Rock (with mineral inclusions)
Geode with Quartz and possibly Jasper/Hematite
Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides
Mineral/Sedimentary Geode
Quartz Pebble
Silicon Dioxide (SiO2)
Mineral / Sedimentary component
Marble
Metamorphosed Limestone/Dolomite
metamorphic
Limonite (Iron Ore/Hydrated Iron Oxide)
Limonite (mixture of FeO(OH)·nH₂O minerals, mainly Goethite, FeO(OH) and Lepidocrocite, FeO(OH))
Mineral
Quartz (likely a macrocrystalline variety like milky quartz or smoky quartz, given the appearance in the image)
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Orthoclase Feldspar (or K-Feldspar)
Orthoclase (KAlSi3O8)
Mineral
Banded Gneiss
Gneiss (variable mineral composition)
metamorphic
Quartz (Rock Crystal) with minor impurities
Quartz (SiO2)
Mineral
Chalcopyrite
Chalcopyrite (CuFeS2)
Mineral
Blue Quartz
Quartz (SiO2) with inclusions
Mineral