Granodiorite with Biotite Mica
Granodiorite (containing Quartz, Plagioclase Feldspar, and Biotite Mica)
igneous
Category
Sedimentary Or Igneous (Secondary Formation)
Browse sedimentary or igneous (secondary formation) specimens identified by the Rock Identifier community.
Sandstone
Arenite (primarily Quartz SiO2)
sedimentary
Limestone (specifically Marl or Chalk)
Calcium Carbonate (CaCO3)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Basalt Column Section
Columnar Basalt (Mafic Extrusive Igneous Rock)
igneous
Granitic Pegmatite
Phaneritic Granite with Potassium Feldspar (KAlSi3O8), Quartz (SiO2), and Plagioclase
igneous
Jasper (likely Polychrome or Mookaite variants)
Silicon Dioxide (SiO2) with iron oxide and hydroxide inclusions
sedimentary (chemically precipitated)
Basalt
Basalt (extrusive igneous rock)
Igneous
Banded Agate
Cryptocrystalline Quartz (SiO2)
mineral
Yellow Quartz (Citrine appearance)
Silicon Dioxide (SiO2)
mineral
Blue Sapphire (Tumbled/Polished)
Corundum (Al2O3)
mineral
Pink Sapphire
Corundum (Al2O3) with Chromium/Iron/Titanium trace impurities
mineral
Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
Mineral
Milky Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Coarse-grained Granite
Granitoid (KAlSi3O8 + SiO2 + NaAlSi3O8)
igneous
Iron-Stained Quartz Pebble
Silicon Dioxide (SiO2) with Iron Oxide (Limonite/Goethite) inclusions
mineral
Epidote in Quartz
Epidote (Ca2(Al,Fe)3(SiO4)3(OH)) in Milky Quartz (SiO2)
metamorphic
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
mineral
Black Sapphire (Basaltic Blue Sapphire)
Corundum (Al2O3)
mineral
Limonite-stained Quartz
Silicon Dioxide (SiO2) with Iron Oxide/Hydroxide (FeO(OH)·nH2O) staining
mineral
Quartz (with Iron staining)
Silicon Dioxide (SiO2)
mineral
Iron-stained Milky Quartz
Silicon Dioxide (SiO2) with iron oxide inclusions
mineral
Gold and Silver (in jewelry form)
Gold (Au) and Silver (Ag)
mineral
Granite
Granite (Phaneritic Igneous Rock)
Igneous
Cobaltian Calcite (Cobaltoan Calcite)
Cobaltian Calcite (CaCO3 with Co2+ substitution)
Mineral
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock including secondary mineral infills)
Igneous
Basalt with Quartz/Epidote Vein
Mafic volcanic rock (formula primarily (Mg, Fe)2SiO4 and CaAl2Si2O8)
igneous
Vesicular Basalt (Scoria)
Extrusive Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
igneous
Quartz Geode
Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity
mineral
Tufa
Calcareous Tufa (CaCO3)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Limonite (Iron Stone Concretion)
Limonite (Hydrous Iron Oxide) - FeO(OH)·nH2O
mineral
Quartz
Quartz (SiO₂)
Mineral
Moss Agate
SiO2 (Silicon Dioxide) with dendritic inclusions
Mineral
Porphyritic Rhyolite (Red)
Rhyolite (Porphyry)
igneous
Milky Quartz Pebble
Silicon Dioxide (SiO2)
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
Banded Agate (Carnelian type)
Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony
mineral
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Mineral
Smoky Quartz Cluster
Smoky Quartz (Silicon Dioxide - SiO2)
mineral
Ferruginous Quartz
Quartz (Silicon Dioxide, SiO2) with Iron Oxides
mineral