Polished white chalcedony or milky quartz pebble
Chalcedony, microcrystalline quartz (SiO₂), possibly with iron-oxide staining or a minor mineral inclusion
mineral
Category
Man Made Glass (Not A Natural Rock Or Mineral)
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Sandstone
Clastic sedimentary rock (Quartz arenite)
sedimentary
Chalk
Micrite (primarily Calcium Carbonate, CaCO3)
sedimentary
Red-and-white jasper/chalcedony pebble
Microcrystalline quartz (SiO₂), likely hematite- or iron-oxide-bearing jasper with white chalcedony/quartz
mineral
Diamond
Carbon (C)
gemstone
Diamond
Carbon (C)
gemstone
Greenstone / serpentinite carving
Serpentinite, chiefly serpentine-group minerals (antigorite, lizardite, or chrysotile); exact identification requires testing
metamorphic
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)
igneous
Citrine
Silicon Dioxide (SiO2)
mineral
Pink Granite
Phaneritic Felsic Igneous Rock (composed of orthoclase, quartz, and plagioclase)
igneous
Sandstone
Arenite (primarily Quartz Arenite)
sedimentary
Obsidian
Obsidian (volcanic glass, amorphous silica rich rock)
Igneous
Beaded mineral/crystal jewelry (likely turquoise and coral accents)
Variable; blue beads may be turquoise (CuAl6(PO4)4(OH)8·4H2O), with possible dyed howlite, glass, or composite materials
gemstone
Sandstone
Arenite (primarily SiO2)
sedimentary
Granite
Phaneritic Felsic Igneous Rock
igneous
Diamond
Carbon (C)
gemstone
Chert / River Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite
sedimentary
Slag Glass / Industrial Slag
Anthropogenic Glass
man-made glass / industrial byproduct
Sandstone
Clastic Sedimentary Rock
sedimentary
Tumbled chert or jasper pebble
Microcrystalline quartz (SiO₂), likely chert/jasper
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Blue glassy cabochon, likely blue quartz or synthetic glass
Possibly dyed blue chalcedony/quartz (SiO₂); visual identification is inconclusive
gemstone
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3)
sedimentary
Diamond
Carbon (C)
gemstone
Asphalt
Asphalt concrete (engineered material, not a naturally occurring rock/mineral in this form)
Sedimentary
Diamond (Cluster Ring)
Carbon (C)
mineral
Chert
Silicon dioxide (SiO2)
Sedimentary
Coquina
Biogenic Limestone (CaCO3)
sedimentary
Blue-and-white opalite sphere
Opalite (commercial synthetic or glass-based imitation; not true opal), typically silica glass or synthetic opalescent material
mineral
Sandstone
Arenite (SiO2 based)
sedimentary
Sandstone
Arenite (SiO2 based typically)
sedimentary
Beach Pebble (Chalcedony / Chert)
Silicon Dioxide (SiO2)
mineral
Blue Chalcedony (likely dyed Agate)
Silicon Dioxide (SiO₂)
mineral
Obsidian
Volcanic Glass (Amorphous silicon dioxide with impurities)
igneous
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
sedimentary
Diamond
Carbon (C)
mineral
Diamond
Diamond (pure Carbon, C)
mineral
Rough Diamond
Pure Carbon (C)
mineral
Obsidian
Volcanic Glass
igneous
Red coral (likely precious coral)
Corallium sp.; calcium-carbonate skeleton, primarily calcite
gemstone
Chert (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
sedimentary