Dendritic Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O) with Manganese or Iron Oxide inclusions
mineral
Category
Sedimentary And Igneous (Mixed)
Browse sedimentary and igneous (mixed) specimens identified by the Rock Identifier community.
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Quartz (Milky Quartz)
Quartz (SiO2 - Silicon Dioxide)
Mineral
Basalt River Stone
Basalt (Aphanitic Mafic Igneous Rock)
igneous
Garnet (Red Garnet)
Garnet Group. The red varieties seen in jewelry are typically Almandine (Fe3Al2(SiO4)3), Pyrope (Mg3Al2(SiO4)3), or a mix of the two (pyrope-almandine series).
Mineral (specifically, a variety of the mineral species Pyrope-Almandine Garnet)
Garnet (likely Almandine or a blend)
Garnet group: X3Y2(SiO4)3, where X can be Ca, Mg, Fe2+, Mn2+ and Y can be Al, Fe3+, Cr3+. Given the dark, somewhat reddish-brown appearance in the image, it's likely Almandine (Fe3Al2(SiO4)3) or a mix with other iron-rich garnets.
Mineral
Quartz (likely Milky Quartz)
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Greenstone
Metamorphosed Mafic Igneous Rock
metamorphic
Quartz (various varieties)
SiO₂ (Silicon Dioxide)
Mineral
Banded Agate (specifically Botryoidal/Orbicular Agate)
Silicon Dioxide (SiO2)
Mineral (variety of Chalcedony/Quartz)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Yellow Quartz Pebble (Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
mineral
Sandstone (Red)
Arenite (primarily Quartz, SiO2, with Iron Oxide cement)
sedimentary
Calcite
Calcite (CaCO3)
mineral
White Quartz
Quartz (SiO2)
Mineral
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Granitic Gneiss
Gneiss (high-grade metamorphic rock primarily of quartz, feldspar, and mica)
metamorphic
Banded Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Jasper
Silicon Dioxide (SiO2) - a variety of Chalcedony (Cryptocrystalline Quartz)
Mineral
Quartz (Milky/Smoky variety on matrix)
Silicon Dioxide (SiO2)
mineral
Quartz (Pebble)
Quartz (SiO₂)
Mineral
Quartz
Quartz (SiO2, Silicon Dioxide)
Mineral
Gneiss (specifically Biotite Gneiss)
Gneiss (high-grade metamorphic rock primarily composed of Silicates)
metamorphic
Agate Geode
Chalcedony (SiO2 - Silicon Dioxide)
sedimentary (secondary mineral formation)
Magnetite / Iron-Rich Concretion
Magnetite (Fe3O4) or Bog Iron Limonite
mineral
Graphite
Graphite (C)
mineral
Hematite
Hematite (Fe2O3)
mineral
Micaceous Rock (likely Muscovite Schist/Gneiss or a Muscovite-rich Specimen)
Predominantly Muscovite (KAl2(AlSi3O10)(F,OH)2), often found in rocks like Muscovite Schist or Muscovite Gneiss.
Metamorphic, Mineral (within a rock type)
Gneiss (specifically a weathered or stream-worn specimen)
Gneiss (Foliated Metamorphic Rock)
metamorphic
Banded Gneiss
Gneiss (Metamorphic high-grade rock)
metamorphic
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Red Jasper (Opaque Chalcedony)
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
mineral
Banded Gneiss
Gneiss (Metamorphic high-grade rock)
metamorphic
Almandine Garnet
Iron aluminum silicate (Fe3Al2(SiO4)3)
Mineral
Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
River Stone / Pebble
Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)
Mineral, Sediment
Gneiss
Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica/Amphibole)
metamorphic
Granite Gneiss
Gneiss (High-grade regional metamorphic rock)
Metamorphic
Red Jasper
Jasper (a variety of Quartz, SiO2)
Mineral