Banded Agate
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Category
Synthetic (Not A Natural Rock)
Browse synthetic (not a natural rock) specimens identified by the Rock Identifier community.
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Fossil Coral and Quartz Pebble
Fossilized Anthozoa / Silicon Dioxide (Quartz)
sedimentary
Black Beach Pebble / Basalt Pebble
Basalt / Mafic Volcanic Rock
igneous
Goldstone
Not a natural mineral or rock. It is an ornamental glass.
Manufactured Glass (Simulant)
Yellow Quartz Pebble (Citrine or Iron-Stained Quartz)
Silicon Dioxide (SiO2)
mineral
Mixed tumbled gemstone collection
Varied minerals, likely including amethyst, sodalite/lapis lazuli, quartzite or aventurine, jasper, and agate/chalcedony
gemstone
Smoky Quartz
Silicon Dioxide (SiO2) with natural radiation treatment
mineral
Decomposed Granite
Grano-diorite/Granite-residuum (SiO2 primary)
igneous
Chert Concretion (Flint)
Silicon Dioxide (SiO2)
sedimentary
Quartz Druzy on Agate (River Cobble)
Silicon Dioxide (SiO2)
Mineral / Sedimentary (often associated with volcanic hosts)
Sandstone (likely Arkosic or Lithic Sandstone)
Clastic Sedimentary Rock (SiO2 with assorted minerals)
sedimentary
Blue Dyed Agate
Silicon Dioxide (SiO2) with artificial pigment
mineral
Amethyst (Tumbled)
Quartz (Silicon Dioxide, SiO2) with iron impurities
mineral
Citrine Geode
Silicon Dioxide (Quartz variety, often heat-treated amethyst): SiO2
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Copper slag or vesicular basalt with copper minerals
Industrial slag / Basaltic matrix with secondary copper minerals
igneous
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Sandstone (Arkose/Quartzose)
Arenite (SiO2 based clastic rock)
sedimentary
Flagstone
Sedimentary Sandstone / Flagstone
sedimentary
Porphyritic Basalt (Porphyry pebble)
Porphyritic Basalt / Amygdaloidal Basalt
igneous
Tumbled gray feldspar-rich stone, possibly granite or quartzite
Indeterminate; likely quartz–feldspar aggregate, potentially fine-grained granite or quartzite
igneous
Sandstone (Pebble)
Sandstone (composed mainly of Quartz, SiO2, with feldspar and lithic fragments)
sedimentary
Quartz (Rose Quartz / Quartz Pebble)
Silicon Dioxide (SiO2)
mineral
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
mineral
Sandstone with Iron Staining
Arenite (SiO2 with Fe2O3)
sedimentary
Speckled rounded stone, likely granite or granitic gneiss
Granite/granitic gneiss; primarily quartz (SiO₂), feldspar, and dark mica or amphibole
igneous
Sandstone
Arenite
sedimentary
Sandstone Pebble
Arenite (primarily SiO2)
sedimentary
Sandstone (Calcareous or Ferruginous)
Clastic sedimentary rock (SiO2 with CaCO3 or Fe2O3 cement)
sedimentary
Sandstone
Arenite (specifically Iron-stained Quartz Sandstone)
sedimentary
Sandstone pebble
Sandstone (SiO2 with iron oxides)
sedimentary
River Pebble (Siltstone / Fine Sandstone)
Sedimentary Rock (siliciclastic clastic rock)
sedimentary
Herkimer Diamond
Quartz (Silicon Dioxide, SiO2)
mineral
Sandstone
Quartzose Sandstone (Sedimentary Rock)
sedimentary
Rounded beach pebble
Lithology indeterminate; likely fine-grained sandstone, mudstone, or weathered volcanic rock
sedimentary
Crushed Granite and Quartz Gravel
Composite Igneous and Silicate Rock Aggregate
igneous
Sandstone
Clastic sedimentary rock (Quartz arenite)
sedimentary
Sandstone (River Cobble)
Sandstone (primarily composed of silica, SiO2)
sedimentary
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily Quartz - SiO2)
sedimentary
Sandstone
Sandstone (SiO2-rich framework with variable matrix)
sedimentary
Sandstone
Arenite (SiO2 based)
sedimentary
Green Sandstone Pebble (River/Beach Pebble)
Glauconitic Sandstone
sedimentary