Chalcedony Geode
Chalcedony (SiO2) within a geode structure
Category
Browse sedimentary (microcrystalline silicate) specimens identified by the Rock Identifier community.
Chalcedony Geode
Chalcedony (SiO2) within a geode structure
Clear Quartz (beads in a bracelet)
Quartz (SiO2)
Flint
Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)
Chalcedony
Chalcedony (SiO₂)
Concretion or Geode (unbroken)
Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.
Quartz Geode (likely within Limestone or Dolomite matrix)
Quartz (SiO₂)
Quartz (likely a clear or rock crystal variety)
Quartz (SiO2 - Silicon Dioxide)
Quartz Druse (on Chalcedony/Agate base)
Silicon Dioxide (SiO2)
Pink Opal / Peruvian Opal
Hydrated amorphous silicon dioxide (SiO2·nH2O)
Rock Crystal Quartz
Quartz (SiO₂)
Shale or Slate with Quartz Veins
Shale (fine-grained clastic sedimentary rock) or Slate (low-grade metamorphic rock formed from shale) with Quartz (SiO2) veins
Chert (or Flint)
Silicon dioxide (SiO2)
Agate
Agate (a variety of Chalcedony, SiO2)
Petrified Wood
Silicified wood (primarily SiO2)
Yellow Chalcedony
Chalcedony (a cryptocrystalline variety of Quartz, SiO₂)
Quartz
Quartz (SiO2)
Quartz
Quartz (SiO2 - Silicon Dioxide)
Opal
Hydrous silicon dioxide (SiO2·nH2O)
Fuchsite Quartzite
Fuchsite-bearing Quartzite
Red Jasper
Jasper (a variety of Quartz, SiO2)
Chert / Flint
Chert (varieties include Flint)
Quartz
Quartz (SiO₂)
Agate
Agate (a cryptocrystalline variety of Quartz, SiO₂)
Chert Pebble (Jasperoid/Flint)
Silicon Dioxide (SiO2) - cryptocrystalline quartz
Blue Chalcedony
Chalcedony (a cryptocrystalline variety of Quartz - SiO₂)
Quartz
Quartz (Silicon Dioxide - SiO2)
Conglomerate
Conglomerate (a clastic sedimentary rock)
Quartz
Quartz (SiO₂)
Ferruginous Sandstone
Sandstone, Iron-rich
Ocean Jasper
Silicon Dioxide (SiO2)
Sodalite (blue beads) and Clear Quartz (clear beads)
Sodalite: Na4Al3Si3O12Cl; Quartz: SiO2
Quartz (Pebble)
Quartz (SiO₂)
Carnelian
Carnelian (a variety of Chalcedony, SiO2)
Mookaite Jasper
Siliceous (chert) sedimentary rock, a form of Jasper
Blue Quartz
Quartz (SiO2) with inclusions
Red Jasper
Jasper (a variety of Chalcedony, SiO₂ with iron oxide inclusions)
Chert (Jasper Variant likely)
Silicon Dioxide (SiO2)
Amethyst
Quartz (SiO2) variety
Red Jasper (possibly)
Jasper (a variety of Chalcedony, SiO2)
Milky Quartz
Quartz (SiO₂)
Quartz (Crystal/Druzy Quartz)
Quartz (SiO₂)
Quartz
Quartz (SiO2)