Chert
Microcrystalline Quartz (SiO2)
Category
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
Chert
Microcrystalline Quartz (SiO2)
Gold in Quartz
Hydrothermal Quartz with Native Gold (SiO2 with Au)
Quartz Crystal Cluster
Silicon Dioxide (SiO2)
Dendrite (Manganese Oxide Dendrites)
Psilomelane or Pyrolusite on Matrix (typically MnO2)
Blue calcite
Calcite (CaCO₃), blue variety
Blue Agate (Dyed)
Silicon Dioxide (SiO2) - Variety of Chalcedony
Greenstone with Epidote or Quartz veins
Metabasalt (Greenstone facies)
Polished blue calcite
Calcite (CaCO₃), likely blue banded or massive calcite
Sunstone
Oligoclase (Plagioclase Feldspar) with inclusions - (Ca, Na)((Al, Si)4O8)
Green Druzy Quartz (Prasiolite)
Silicon Dioxide (SiO2) with inclusions (typically Chlorite or Actinolite)
Quartz Geode
Silicon Dioxide (SiO2)
Bumblebee Jasper
Anhydrite-Aragonite mixture with Orpiment and Realgar
Chert (Flint)
Cryptocrystalline Quartz (SiO2)
Chert (Green Chert or Jasper)
Silicon Dioxide (SiO2)
Chert (Flint)
Chert (SiO2)
Chert Nodule (Flint)
Cryptocrystalline quartz (SiO2)
Septarian Pebble
Septarian nodule / Concretion
Quartz Geode
Silicon dioxide (SiO2)
Yellow Calcite
Calcium Carbonate, CaCO3
Celestite
Celestine (SrSO4)
Slag (Industrial Glass)
Artificial Vitreous Silicate
Sea Glass
Amorphous Silica (SiO2) with various additives
Asphalt (Bituminous pavement)
Bituminous concrete / Asphalt
Shale creek bed
Shale (fine-grained clastic sedimentary rock)
Amygdaloidal Basalt with Agate/Zeolite Amygdules
Basalt (extrusive igneous rock) containing secondary mineral fillings
Geode (Quartz / Chalcedony Geode)
SiO2 (Silicon Dioxide)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Chrysocolla
Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O)
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
Quartz (Milky/Crystalline fragment)
Silicon Dioxide (SiO2)
Pyrite in Quartz
Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)
Chrysocolla
Hydrated copper phyllosilicate, (Cu,Al)2H2Si2O5(OH)4·nH2O
Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
Chert / Flint
Cryptocrystalline quartz (SiO2)
Quartz Crystal Cluster
Silicon Dioxide (SiO2)
Botryoidal quartz (likely milky quartz)
Quartz, silicon dioxide (SiO₂)
Quartz Geode (with Calcite influence)
Silicon Dioxide (SiO2) with possible Calcium Carbonate (CaCO3)
Quartz Geode with Calcite
Silicon Dioxide (SiO2) and Calcium Carbonate (CaCO3)
Jasper
Microcrystalline Quartz (SiO2)
Amethyst
Quartz (Silicon Dioxide, SiO2) with iron impurities
Banded Agate (specifically Sardonyx or Black Agate variety)
Silicon Dioxide (SiO2) - Chalcedony / Cryptocrystalline Quartz
Limonite / Iron Oxide Concretion
FeO(OH)·nH2O (Hydrated iron oxide)