Amethyst
Amethyst (SiO2 - Silicon Dioxide with iron impurities)
mineral
Category
Sedimentary Or Igneous
Browse sedimentary or igneous specimens identified by the Rock Identifier community.
Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Carnelian Agate
Carnelian (Silicon Dioxide: SiO2) with iron oxide impurities
mineral
Gneiss
Foliated Metamorphic Rock (Gneiss)
metamorphic
Black Obsidian and Hematite
Volcanic Glass (SiO2) and Hematite (Fe2O3)
igneous and mineral
Gneiss
Gneiss
metamorphic
Hematite
Iron(III) oxide (Fe2O3)
mineral
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Dendritic Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O) with Manganese or Iron Oxide inclusions
mineral
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
Quartz (various varieties)
SiO₂ (Silicon Dioxide)
Mineral
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
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
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
Graphite
Graphite (C)
mineral
Quartz (Pebble)
Quartz (SiO₂)
Mineral
Quartz
Quartz (SiO2, Silicon Dioxide)
Mineral
Hematite
Hematite (Fe2O3)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
Mineral / Sedimentary
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
Garnet (likely Almandine, Pyrope, or a blend)
Garnet group minerals: X3Y2(SiO4)3, where X and Y represent various metal ions (e.g., Almandine: Fe3Al2(SiO4)3, Pyrope: Mg3Al2(SiO4)3)
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
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Banded Gneiss
Gneiss (Metamorphic high-grade rock)
metamorphic
Milky Quartz
Silicon Dioxide (SiO2)
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