Quartz
Silicon dioxide (SiO2)
Mineral
Category
Sedimentary Or Igneous (Secondary Formation)
Browse sedimentary or igneous (secondary formation) specimens identified by the Rock Identifier community.
Learn about Sedimentary Or Igneous (Secondary Formation) in the encyclopedia
View all →
Blue Apatite
Apatite (Ca5(PO4)3(F,Cl,OH))
mineral
Weathered schist or gneiss cobble
Foliated silicate rock, likely mica schist or biotite gneiss
metamorphic
Banded Chert (with Quartz Vein)
Microcrystalline Silica (SiO2)
sedimentary
Gneiss
Gneissic Metamorphic Rock
metamorphic
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2
mineral
Quartz with Iron Oxide Staining
SiO2
mineral
Carnelian Agate
Chalcedony (SiO2) with iron oxide inclusions
mineral
Firewood (Wood Log)
Lignum (Plant tissue composed of cellulose and lignin)
Organic (Non-geological)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
mineral
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
igneous
Weathered schist or gneiss
Quartz–feldspar–mica metamorphic rock
metamorphic
Likely mica-rich metamorphic rock (schist)
Mica schist, probably biotite–muscovite schist; exact identification requires closer examination
metamorphic
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Basalt
Mafic Igneous Rock (composed primarily of pyroxene and calcium-rich plagioclase)
igneous
Vesicular basalt (possible scoria)
Basaltic volcanic rock; chiefly plagioclase, pyroxene, and iron-rich minerals, with vesicles formed by trapped gas
igneous
Botryoidal hematite (ironstone)
Hematite, Fe₂O₃
mineral
Agate (Grey Agate Slice)
Microcrystalline Quartz (SiO2)
mineral
K2 Jasper (K2 Granite)
Azurite in Granite (Biotite Granite with Azurite inclusions)
igneous
Red Garnet (likely Almandine or Pyrope)
Garnet group: X3Y2(SiO4)3 (e.g., Almandine: Fe3Al2Si3O12)
mineral
Geode
Silicon Dioxide (Quartz/Chalcedony) in carbonate or volcanic host rock
sedimentary
Likely weathered metamorphic rock (possibly schist or gneiss)
Indeterminate; probable mica-rich quartz–feldspar metamorphic rock
metamorphic
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Tumbled magnetite (likely)
Magnetite, Fe₃O₄; possibly magnetite-rich ironstone
mineral
Grey Banded Agate
Silicon Dioxide (SiO2)
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
mineral
Quartz–mica schist or mica-rich quartzite
Quartz with muscovite/biotite mica; likely a quartz-mica schist, possibly pegmatitic
metamorphic
Weathered basalt fragment
Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, with possible olivine and iron-oxide alteration
igneous
Vesicular volcanic rock, likely pumice or scoriaceous rhyolite
Highly vesicular felsic volcanic rock; commonly rhyolitic pumice (composition dominated by volcanic glass, quartz, and alkali feldspar)
igneous
Gold Nugget
Native Gold (Au)
mineral
Quartz-veined Metamorphic Pebble
Silicate-rich metamorphic rock with quartz veins (SiO2)
metamorphic
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Magnetite (potentially Hematite-rich)
Magnetite (Fe3O4)
mineral
Amygdaloidal Basalt
Extrusive Igneous Rock with Amygdules
igneous
Yellow chalcedony or quartz fragment
Microcrystalline quartz, SiO₂ (tentative; possibly iron-stained chalcedony)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Carnelian
SiO2 (Silicon Dioxide, variety of Chalcedony)
mineral
Dark metamorphic rock, likely biotite schist or gneiss
Quartz–feldspar–biotite metamorphic rock; exact identification requires a fresh surface and testing
metamorphic
Quartz
Silicon dioxide (SiO2)
Mineral
Carnelian Agate
Carnelian (Silicon Dioxide - SiO2)
sedimentary