Quartz Geode
Crystalline Silica (SiO2)
Category
Browse sedimentary (volcanic) specimens identified by the Rock Identifier community.
Quartz Geode
Crystalline Silica (SiO2)
Pink Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O)
Tumbled Agate
Silicon dioxide (SiO2)
Chert on Volcanic Host Rock
Sedimentary Chert (SiO2) within Basalt or Andesite
Banded Agate (Jasper-Agate)
Silicon Dioxide (SiO2)
Rough amber-like brown mineral specimen
Uncertain from photograph; possibly iron-stained quartz, common opal, or resinous amber
Red Jasper (or Banded Jasper)
Silicon Dioxide (SiO2 with Hematite impurities)
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
Jasper
Silicon dioxide (SiO2)
Yellow Jasper
Silicon dioxide (SiO2)
Geode (Unopened)
Silica-rich concretion (SiO2)
Common Opal / Chert
Hydrated silica (SiO2·nH2O) or Microcrystalline Quartz (SiO2)
Quartz Geode Fragment
Crystalline Silicon Dioxide (SiO2)
Red Jasper
Silicon Dioxide (SiO2) with iron oxide impurities
Jasper
Jasper (Silicate mineral, SiO2)
Brown Chalcedony
Silicon Dioxide (SiO2)
Chert (Jasper variation)
Silicon Dioxide (SiO2)
Rounded basalt pebble
Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, commonly with olivine
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions), SiO2
Rounded dark river pebble
Likely fine-grained basalt or andesite; exact identification requires a fresh surface or tests
Pyrite-rich Volcanic Rock
Iron Disulfide (FeS2) in Volcanic Matrix
Jasper
Microcrystalline Quartz (SiO2)
Quartz Geode (Cracked)
Silicon Dioxide (SiO2)
Agate Nodule
Silicon Dioxide (Quartz/Chalcedony), SiO2
Agate
Silicon Dioxide (Quartz), SiO2
Carnelian or Red Agate
Chalcedony (SiO2)
Chalcedony (Pancawarna / Bacan / Red Chalcedony Agate Ring)
Silicon dioxide (SiO2)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Agate Pebble
Silicon dioxide (SiO2) - Chalcedony variety
Quartz (Agate/Chalcedony)
Silicon Dioxide (SiO2)
Jasper
Microcrystalline quartz (SiO2)
Jasper
Microcrystalline Quartz (SiO2)
Hematite
Hematite (Fe2O3)
Quartz (Agate/Chalcedony)
Silicon Dioxide (SiO2)
Jasper
Silicon dioxide (SiO2) with impurities, microcrystalline quartz
Polychrome Jasper
Microcrystalline Quartz (SiO2)
Jasper
Silicon Dioxide (SiO2) with impurities
Jasper
Microcrystalline Quartz (SiO2)
Yellow Jasper
Silicon dioxide, SiO2
Carnelian
Silicon Dioxide (Chalcedony variety), SiO2
Chalcedony (Agate / Quartz Nodule)
Silicon Dioxide (SiO2)