Chert (Flint)
Silicon Dioxide (SiO2)
Category
Browse man made rock (sedimentary analogue) specimens identified by the Rock Identifier community.
Chert (Flint)
Silicon Dioxide (SiO2)
Blue chalcedony (likely dyed or treated)
Microcrystalline quartz, SiO₂ (chalcedony)
Sandstone
Arenite (primarily SiO2)
Opalite
Synthetic glass (SiO2 + metal additions)
Sandstone
Arenite (SiO2 primarily)
Tumbled milky chalcedony (likely common opalite-like quartz)
Chalcedony, microcrystalline SiO₂; possibly pale common opal, hydrated SiO₂·nH₂O
Raw quartz crystal
Quartz (silicon dioxide, SiO₂), likely milky or included quartz
Sandstone
Arenite (composed primarily of SiO2)
Limestone
Sedimentary Rock (Primarily CaCO3)
Carborundum
Silicon Carbide (SiC)
Opalite
Synthetic Opalised Glass
Sandstone
Arenite
Chert
Silicon dioxide (SiO2)
Sandstone
Sedimentary Rock (Quartz Sandstone)
Sandstone (likely Quartzose)
Clastic sedimentary rock (SiO2 primary)
Sandstone
Arenite (primarily SiO2)
Sandstone (Quartz Arenite)
Sandstone (dominated by SiO2 quartz grains)
Obsidian (likely black volcanic glass)
Obsidian; primarily amorphous volcanic silica glass, approximately SiO₂-rich rhyolitic composition
Cullet (Slag Glass)
Amorphous Silica (Industrial byproduct)
Sandstone
Arenite (composed primarily of SiO2)
Sandstone
Sedimentary Rock (Quartz Sandstone)
Chert (specifically Tan/Gray Chert)
Microcrystalline quartz (SiO2)
Sandstone
Sandstone (composed predominantly of Quartz, SiO2, with Feldspar and Clay minerals)
Sandstone
Arenite (variable SiO2 composition)
Chert (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
Opalite-style pendant (likely synthetic glass, not natural opal)
Opalescent glass; commonly sold as “opalite” (not a recognized mineral species)
Sandstone
Arenite (composed primarily of SiO2)
Chert Nodule
Microcrystalline Quartz (SiO2)
Pink Cubic Zirconia (CZ)
Zirconium Dioxide (ZrO2)
Sandstone
Clastic sedimentary rock (Quartz arenite/Arkose)
Blue Goldstone
Synthetic Avanturine Glass (or Aventurine Glass)
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
Unidentified gray stone/concrete-like fragment
Indeterminate; likely a fine-grained carbonate or cementitious geological fragment
Chalk
Calcium carbonate (CaCO3)
Chalk
Calcium Carbonate (CaCO3)
Tumbled black stone, likely black obsidian
Obsidian; volcanic glass, typically rhyolitic composition (SiO₂-rich)
Aventurine
Quartz containing inclusions of Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
Ferro-silicate Slag
Industrial Vitrified Slag (High-silica amorphous glass)
Brecciated Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Green glassy mineral fragment, possibly fluorite
Fluorite (calcium fluoride, CaF₂), tentative identification
Terracotta (Man-made ceramic brick fragment)
Baked clay / High-iron ceramic (Silicate-based ceramic)
Weathered chert or chalcedony nodule
Microcrystalline quartz (SiO₂), possibly silicified limestone or agate-like chalcedony