Black Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Category
Sedimentary (Volcanic)
Browse sedimentary (volcanic) specimens identified by the Rock Identifier community.
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Carnelian (Chalcedony)
Silicon Dioxide (SiO2)
mineral
Quartz Vein in Host Rock (Breccia/Rhyolite)
Silicon Dioxide (SiO2) with matrix
Mineral in Igneous/Sedimentary host
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides
sedimentary
Carnelian Agate
Silicon Dioxide (SiO2) with iron oxide impurities
mineral
Common Opal
Hydrated silica (SiO2 "n"H2O)
mineral
Black Opal (Kalimaya)
Hydrated Silica (SiO2·nH2O)
mineraloid
Jasper and Agate Beads (Mahogany Obsidian, Dyed Agate, Turquoise/African Turquoise)
Silicon Dioxide (SiO2) mixture with inclusions / Hydrated Copper Aluminum Phosphate
gemstone
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Red Jasper
Silicon Dioxide (SiO2)
sedimentary
Polished Jasper (Mushroom Carving)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Blue Chalcedony
Silicon Dioxide (SiO2)
mineral
Bumblebee Jasper
Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)
igneous
Imperial Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Mineral Inclusions
Sedimentary
Sulfur
Native Sulfur (S8)
mineral
Black onyx or black obsidian bead bracelet
Likely chalcedony (microcrystalline quartz, SiO₂) if onyx; alternatively volcanic glass (obsidian)
gemstone
Red jasper (likely brecciated or iron-stained jasper)
Jasper, microcrystalline quartz (SiO₂), colored chiefly by iron oxides
metamorphic
Amethyst Geode
Amethyst (Silicon Dioxide), Formula: SiO2
mineral
Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
sedimentary
Agate Nodule
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Quartz Geode
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2) in a Sedimentary Host
mineral
Polished orbicular jasper
Silicified volcanic tuff or rhyolitic jasper; chiefly microcrystalline quartz (SiO₂) with iron-oxide-rich orbicules
sedimentary
Polymictic breccia, possibly volcanic breccia
Polymictic clastic breccia; likely a matrix-supported breccia containing lithic fragments, quartz, feldspar, and dark mafic minerals
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Silicon dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Chert (Common Opal/Jasper transition)
Silicon Dioxide (SiO2)
sedimentary
Agate
Silicon dioxide (Chalcedony), SiO2
sedimentary
Blue Chalcedony
Silicon dioxide (SiO2)
mineral
Quartz (Chalcedony)
Silicon Dioxide (SiO2)
mineral
White Chalcedony
Silicon Dioxide (SiO2)
mineral
Green Chalcedony Ring
Silicon Dioxide (SiO2)
gemstone
Blue Chalcedony
Cryptocrystalline Quartz (SiO2)
mineral
Chalcedony (Agate/Carnelian)
Cryptocrystalline Quartz (SiO2)
mineral
Sulfur (on Matrix)
Native Sulfur (S8)
mineral
Jasper
Silicon dioxide, SiO2
Mineral
Chalcedony Geode
Silicon Dioxide (SiO2)
mineral
Dark gray volcanic rock, probably andesite or basalt
Fine-grained mafic–intermediate volcanic rock; likely basalt (plagioclase ± pyroxene), possibly andesite
igneous
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary