Flint
Silicon dioxide (SiO2) - cryptocrystalline quartz
sedimentary
Category
Not A Natural Rock
Browse not a natural rock specimens identified by the Rock Identifier community.
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Jasper Pebble
Microcrystalline Quartz (Chalcedony), SiO2
sedimentary
Flint / Chert Nodule
Microcrystalline quartz (SiO2)
sedimentary
Chert (River Pebble/Finger Stone)
Microcrystalline quartz (SiO2)
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide (Limonite/Hematite)
mineral
Milky Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz with Iron Stains
Silicon Dioxide (SiO2) with FeOx inclusions
mineral
Fossilized shell or brachiopod
Likely a calcareous brachiopod or bivalve fossil; exact identification requires clearer detail and scale
fossil
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Sedimentary Rock
Blue Goldstone
Man-made glass with suspended copper, cobalt, or manganese particles
man-made glass
Tumbled ruby or ruby-bearing corundum
Corundum (Al₂O₃), red variety colored mainly by chromium
gemstone
Blue Goldstone
Synthetic Avanturine Glass (or Aventurine Glass)
Synthetic Glass
Natural Freshwater Pearl
Calcium Carbonate (Aragonite and Calcite), CaCO3
gemstone
Tumbled dark river pebble, probably basalt
Fine-grained mafic volcanic rock, most likely basalt; exact identification requires testing
igneous
Carved Gemstone Mushroom
Quartz / Feldspar composite (Carved lapidary art)
gemstone
Clear quartz crystal
Quartz (silicon dioxide, SiO₂)
mineral
Rounded brown sandstone or weathered river cobble
Likely quartz-rich sandstone; exact identification requires a fresh surface and tests
sedimentary
Moldavite
Moldavite (Siliceous vitreous substance)
tektite (natural glass)
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Quartz (Iron-stained Quartz Pebble)
Silicon Dioxide (SiO2)
mineral
Red Jasper (Quartz)
SiO2 (Silicon Dioxide with Iron Oxide inclusions)
sedimentary
Septarian Pebble
Septarian nodule / Concretion
sedimentary
Red Jasper with Quartz Veining
Jasper (Silicon Dioxide, SiO2)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Yellow Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Yellow Chalcedony (Agate)
Silicon Dioxide (SiO2)
mineral
Red Quartzite Pebble
Quartzite (SiO2)
metamorphic
Chalcedony Pebble
Cryptocrystalline Quartz (SiO2)
mineral
Chert Geode with Quartz Druzy
Microcrystalline Quartz (SiO2) with macrocrystalline Quartz
sedimentary
Quartzite Pebble
Quartzite (primarily SiO2)
metamorphic
Diamond
Natural Diamond (Carbon, C)
gemstone
Tumbled dark stone, likely basalt or chert
Basalt (fine-grained mafic rock), possibly weathered chert; exact identification requires testing
igneous
Fluorite on Matrix
Calcium Fluoride (CaF2)
mineral
Tumbled greenstone/chlorite-rich pebble
Likely chlorite-rich greenschist or altered basalt; exact identification requires testing
metamorphic
Calcite (likely chalky calcite fragment)
Calcite, calcium carbonate (CaCO₃)
mineral
Diamond
Carbon (C)
gemstone
Diamond (or Diamond Simulant)
Carbon (C) if diamond, various if simulant
gemstone
Quartz (Rock Crystal) with minor impurities
Quartz (SiO2)
Mineral
Grey Slate
Foliated Metamorphic Rock (formed by low-grade regional metamorphism of shale or mudstone)
metamorphic
Concrete fragment or Conglomerate
Artificial Conglomerate (Concrete) or Natural Conglomerate
sedimentary
Smoky Quartz
Silicon Dioxide (SiO2)
mineral