Shale
Argillite / Shaly Mudstone
Category
Browse anthropogenic (man made material processed by nature) specimens identified by the Rock Identifier community.
Shale
Argillite / Shaly Mudstone
Diamond
Carbon (C)
Rough Diamond
Diamond (C)
Diamond
C (Carbon)
Scoria
Vesicular Basaltic Glass
Chert (Holey Stone)
Microcrystalline Quartz (SiO2)
Flint (or Chert)
Microcrystalline quartz (SiO2)
Limestone Cobble
Sedimentary Calcium Carbonate (CaCO3)
Fluorite (likely Green Fluorite variant)
Calcium Fluoride (CaF2)
Tumbled honey-colored chalcedony or quartzite
Microcrystalline quartz, SiO₂; exact identification requires testing
Quartz
Silicon Dioxide (SiO2)
Quartz cluster, possibly druzy quartz on matrix
Quartz (SiO₂), likely microcrystalline to coarse crystalline; associated matrix uncertain
Diamond
Carbon (C)
Scoria
Scoria (Vesicular Basaltic Rock)
Diamond (or Diamond Simulant)
Carbon (C) if diamond, various if simulant (e.g., Cubic Zirconia - ZrO2, Moissanite - SiC)
Sandstone (Quartz-rich)
Arenite (composed mainly of SiO2)
Sandstone (Quartzose)
Arenite (composed primarily of SiO2)
Quartz-lined vesicle in basalt (amygdaloidal basalt)
Amygdaloidal basalt with drusy quartz; predominantly plagioclase, pyroxene, and iron oxides
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Tumbled brown jasper (likely iron-rich chalcedony)
Jasper, opaque microcrystalline quartz (SiO₂), commonly colored by iron oxides
Limestone
Calcium carbonate (CaCO3)
Limestone
Sedimentary rock composed primarily of Calcium Carbonate (CaCO3)
Diamond (or Simulant)
Carbon (C) or various simulants (e.g., Cubic Zirconia)
Sandstone
Arenite (SiO2 based)
Green Slag Glass
Amorphous Silica / Glassy Blast Furnace Slag
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Moss Agate
Moss Agate (a variety of Chalcedony, SiO ₂)
Chert (often called Flint)
Chert (Cryptocrystalline Silica, SiO2)
Diamond
Carbon (C)
Quartz Geode
Silicon Dioxide (SiO2)
Red jasper (likely iron-rich chert)
Microcrystalline quartz (SiO₂), colored by hematite/goethite; possibly brecciated jasper
Jasper
Silicon dioxide (SiO2)
Tumbled jasper, likely red/brown jasper
Microcrystalline quartz (chalcedony), SiO₂, colored chiefly by iron oxides
Banded Agate
Agate (chalcedony variety of Silicon Dioxide, SiO2)
Sandstone
Sedimentary Rock (Quartz arenite / Lithic sandstone)
Sandstone (likely Quartzose)
Arenite (primarily SiO2)
Sandstone
Arenite
Diamond
Natural Diamond (Carbon, C)
Diamond
Natural Diamond (Carbon, C)
Sandstone
Arenite
Polished Picasso jasper
Silicified carbonate rock, commonly marketed as Picasso jasper; composition varies and is not a single mineral species
Diamond (in jewelry setting)
Cubic Carbon (C)