Black Opal
Hydrated silica (SiO2·nH2O)
Category
Browse sedimentary rock (technically a variety of chalcedony) specimens identified by the Rock Identifier community.
Black Opal
Hydrated silica (SiO2·nH2O)
Chert (Nodule)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (Jasper)
Microcrystalline Quartz (SiO2) with iron oxide impurities
Conglomerate
Clastic Sedimentary Rock (Conglomerate)
Scoria
Extrusive Basaltic Scoria
Banded Chert
Microcrystalline Quartz (SiO2)
Obsidian
Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)
Desert Rose
Gypsum (CaSO4·2H2O) or Baryte (BaSO4) with trapped sand grains
Chalcedony (specifically Agate or Common Opal variety)
Cryptocrystalline Silica (SiO2)
Common Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Agate (specifically Chalcedony nodule)
Silicon Dioxide (SiO2)
Chalcedony (Botryoidal or Tumbled)
Chalcedony (SiO₂)
Chert (specifically Flint or Gray Chalcedony)
Microcrystalline Quartz (SiO2)
Banded Chert
Chert (a microcrystalline variety of quartz, SiO2 with minor impurities)
Lapis Lazuli (Lazurite crystals on Marble)
Lazurite / (Na,Ca)8[(S,Cl,SO4,OH)2|(AlSiO4)6]
Chert (Tan/Yellow variety)
Microcrystalline quartz (SiO2)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Obsidian
Volcanic Glass (SiO2 rich)
Chert (Jasper/Chalcedony)
Microcrystalline Quartz (SiO2)
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxide
Banded Agate (specifically Eye Agate / Chalcedony)
Agate (Cryptocrystalline variety of Quartz, SiO2)
Chert (Iron-Stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (often called Jasper in this color)
Microcrystalline quartz (SiO2)
Chert (White/Gray variety)
Chert (SiO2)
Chert (Jasper-bearing)
Chert (Silicon Dioxide, SiO2)
Quartz / Chert
Silicon Dioxide (SiO2)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2
Mookaite Jasper
Radiolarite (SiO2 with impurities)
Chalcedony (Agate/Carnelian variant)
Silicon Dioxide (SiO2)
Chert / Jasper
Microcrystalline Quartz (SiO2)
Quartz (likely Clear Quartz or Rock Crystal)
Quartz (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Picture Jasper
Silicon dioxide (SiO2)
Dyed Agate / Painted Stone
Silicon Dioxide (SiO2) with artificial pigment
Conglomerate
Conglomerate (Clastic Sedimentary Rock)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Green Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 predominantly)
Obsidian
Obsidian (Volcanic Glass)
Sandstone (Graywacke)
Clastic Sedimentary Rock (Lithic Sandstone)
Quartz (Variety: Citrine or Tumbled Chalcedony)
Silicon Dioxide (SiO2)
Agate
Silicon Dioxide (SiO2) - Variety of Chalcedony