Fossiliferous Limestone with Crinoid Stem
Sedimentary Rock with Crinoidea Fossil
fossil
Category
Man Made Rock (Sedimentary Analogue)
Browse man made rock (sedimentary analogue) specimens identified by the Rock Identifier community.
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Green sea glass or tumbled green quartz (uncertain)
Likely quartz (SiO₂) if natural; alternatively man-made soda-lime glass
mineral
Sandstone
Arenite (SiO2 based)
sedimentary
Botryoidal chalcedony (likely agate/jasper variety)
Microcrystalline quartz, SiO₂
mineral
Polished silver sheen obsidian heart
Obsidian (volcanic glass), primarily rhyolitic silica-rich glass
igneous
Blue-green cabochon, likely chalcedony or treated glass imitation
Cryptocrystalline quartz (chalcedony/possibly chrysoprase); identification uncertain from image
gemstone
Limpets Shell / Fossil Specimen
Patellogastropoda (Class)
fossil
Chert (Flint / Jasper)
Silicon Dioxide (SiO2)
sedimentary
Opalite
Synthetic Opalised Glass
mineraloid (synthetic)
Carborundum (Silicon Carbide)
Silicon Carbide (SiC)
mineral (synthetic)
Sandstone (with potential Arkose/Lithic characteristics)
Arenite (Sedimentary rock composed of sand-sized grains)
sedimentary
Sandstone
Arenite (mostly SiO2)
sedimentary
Red-orange cabochon, likely carnelian or glass imitation
Carnelian: chalcedony (microcrystalline SiO₂), commonly iron-colored
gemstone
Slate
Metamorphic Pelitic Rock
metamorphic
Polished black pebble, possibly obsidian
Volcanic glass (obsidian), likely; identification is tentative from the image
igneous
Chert (White Chert/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Titanium Amethyst Geode
Silicon Dioxide (SiO2) with Titanium/Metal Vapor Deposition Layer
mineral
Sandstone
Clastic Sedimentary Rock
sedimentary
Fossil Coral
Scleractinia (Stony Coral) fossil
fossil
Green Glass (often marketed as 'Obsidian' or 'Green Quartz')
Amorphous Silica (SiO2) with copper or chromium additives
Mineraloid (Man-made)
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite (SiO2 composition dominant)
sedimentary
Sea Glass
Amorphous silicon dioxide (Man-made glass weathered by nature)
mineral
Blue glassy tumbled stone, likely blue chalcedony or slag glass
Chalcedony (microcrystalline SiO₂), possibly man-made blue glass
mineral
Sea Glass
Amorphous Silicon Dioxide (Man-made glass weathered by nature)
mineral
Milky quartz (rough fragment)
Quartz, silicon dioxide (SiO₂)
mineral
Sandstone (Pebble)
Sandstone (SiO2 with matrix/cement)
sedimentary
Belemnoit (Fossil)
Belemnoidea (Order), Rostrum / Guard
sedimentary
Goldstone (Red)
Aventurine Glass (SiO2 + Cu)
Synthetic Glass (Often categorized as a simulated mineral)
Ferro-slag (Leland Blue/Slag Glass)
Anthropogenic Vitreous Silica (Industrial Slag)
igneous
Sandstone
Arenite (specifically sublithic or quartz arenite)
sedimentary
Blue Crackle Quartz (Dyed Quarzite)
Silicon Dioxide (SiO2) with artificial dye
Metamorphic (modified)
Dyed Blue Agate (Dragon Vein Agate)
Silicon Dioxide (SiO2) with artificial cobalt/organic dyes
mineral
Diamond
Native Carbon (C)
mineral
Dyed Aura Quartz
Silicon Dioxide (SiO2) with metallic coating
mineral
Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)
Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)
mineraloid / industrial byproduct
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Goldstone (blue/black aventurine glass)
Man-made aventurine glass; silica glass containing metallic copper or other glittering inclusions
mineral
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Sandstone
Arenite (SiO2 based typically)
sedimentary