Psilomelane (Black Hematite/Manganese Ore)
Barium Manganese Oxide (Formula: BaMn9O18(OH)4)
mineral
Category
Sedimentary (Secondary Classification: Cryptocrystalline Quartz)
Browse sedimentary (secondary classification: cryptocrystalline quartz) specimens identified by the Rock Identifier community.
Basalt with Amygdaloidal Inclusions
Aphanitic Mafic Volcanic Rock (Basalt)
igneous
Limonite (Ironstone)
Limonite (FeO(OH)·nH2O)
mineral
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Jasper in Rhyolite matrix
Silicon Dioxide (SiO2) with various inclusions in Felsic Igneous matrix
igneous
Clear Quartz
Silicon dioxide (SiO2)
mineral
Milky Quartz (Water-Worn Pebble)
Quartz (Silicon Dioxide, SiO2)
mineral
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
igneous
Porphyritic Basalt (with Quartz or Calcite inclusion)
Porphyritic Basalt (Matrix: SiO2/MgO/FeO, Phenocryst: likely Quartz or Calcite)
igneous
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified Wood (primarily SiO₂ - Silicon Dioxide)
metamorphic
Banded Agate
Agate (Silicon Dioxide / SiO2)
mineral
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Limonite (Iron Ore)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Volcanic Rock)
Igneous
Basalt with Quartz Veins
Basalt (composition: SiO2, MgO, FeO, Al2O3, CaO)
igneous
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
mineral
Chalcedony (specifically Blue Chalcedony or Common Opal variety)
Silicon Dioxide (SiO₂)
mineral
Pyrite
Iron Pyrite (FeS2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated Iron Oxide)
mineral
Agate
Silicon dioxide (SiO2)
mineral
Basalt with Quartz/Calcite Inclusions
Mafic Volcanic Rock (Fe-Mg silicate rich)
igneous
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Basalt with Quartz/Calcite matrix
Basalt (SiO2 with Ca/Mg/Fe silicates) on a Mineral Matrix
igneous
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
sedimentary
Quartz-veined Basalt
Amygdaloidal or Porphyritic Basalt with Silicon Dioxide (SiO2) vein
igneous
Granite with Orthoclase and Hematite Staining
Phaneritic Felsic Igneous Rock (primarily SiO2 with KAlSi3O8)
igneous
Banded Agate Geode
Silicon Dioxide (SiO2)
mineral
Goethite (Iron Ore)
Goethite (FeO(OH))
mineral
Agate Geode
Silicon Dioxide (SiO2) - Chalcedony / Quartz Variety
Mineral
Red Jasper
Jasper (a variety of Chalcedony, SiO₂)
Mineraloid (cryptocrystalline quartz)
Quartz Crystal
Quartz (SiO₂)
Mineral
Quartz Geode (likely within Limestone or Dolomite matrix)
Quartz (SiO₂)
Mineral within a Sedimentary Rock
Smoky Quartz and Biotite Schist
Quartz-Biotite Schist (SiO2 + K(Mg,Fe)3AlSi3O10(F,OH)2)
metamorphic
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Banded Sandstone (Liesegang Rings)
Sedimentary sandstone with Iron oxide precipitates
sedimentary
Quartz
Quartz (Silicon Dioxide - SiO2)
Mineral
Basalt with Quartz Veins
Amygdaloidal Basalt (matrix) with Crystalline SiO2 (veins)
igneous
Green Agate
Silicon dioxide (SiO₂)
mineral
Quartzite with vugs/druzy quartz
Crystalline Silicon Dioxide (SiO2)
metamorphic