Antropogenic (Man Made)

Sandstone

Arenite (SiO2 composition dominant)

Tumbled quartz-rich pebble

Microcrystalline quartz (SiO₂), possibly milky quartz or quartzite

Blue-green chrysocolla rough specimen

Chrysocolla, hydrated copper aluminosilicate; commonly associated with malachite, quartz, and limonite

Pearl

Organic gemstone (Calcium carbonate - CaCO3)

Chert (variations include Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Diamond

Native Carbon (C)

Sandstone (Quartzose)

Sandstone (SiO2 dominated)

Polished/tumbled brown-and-white mineral fragment

Indeterminate; possibly quartz-rich jasper, brecciated jasper, or an iron-stained quartz mineral

Coal (Bituminous Coal)

Caustobiolith / Sedimentary Rock

Diamond

Carbon (C)

Quartzite

Metamorphic Quartzite (SiO2)

Diamond

Carbon (C)

Diamond

Carbon (C)

Multicolor quartz bead bracelet

Quartz (silicon dioxide, SiO₂); bead colors may be from different varieties or treated quartz

Sandstone

Arenite (composed primarily of SiO2)

Sandstone

Clastic Sedimentary Rock

Quartzite

Metamorphic Quartzite (SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2, often with CaCO3 or Fe2O3 cement)

Diamond

Diamond (pure carbon C)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite

Metamorphic Quartzite (primarily SiO2)

Quartzite

Metamorphic Quartzite (primarily SiO2)

Sandstone

Arenite

Tumbled quartz (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

Quartzite

Metamorphic Quartz Rock (SiO2)

Red Quartzite

Quartzite (Metamorphosed Quartz Arenite)

Tumbled chalcedony pendant (likely agate)

Chalcedony, microcrystalline quartz (SiO₂); the pale bands suggest agate

Likely mica-rich schist (possibly phyllite)

Muscovite–biotite schist; exact identification requires examination of a fresh surface

Diamond

Diamond (pure Carbon, C)

Tumbled blue-green stone, likely chrysocolla or dyed chalcedony

Probable chrysocolla (hydrated copper aluminosilicate; variable composition), though appearance could also represent dyed chalcedony

Sandstone

Arenite (primarily SiO2)

Diamond

Carbon (C)

Sandstone

Sedimentary Rock (Quartz Sandstone)

Diamond (or Cubic Zirconia)

Carbon (C) or Zirconium Dioxide (ZrO2)

Chert (varietal: Flint/Jasper)

Silicon Dioxide (SiO2)

Diamond (or Diamond Simulant)

Carbon (C) or Cubic Zirconia (ZrO2)

Tumbled green aventurine (probable)

Quartzite dominated by quartz (SiO₂), with green mica/fuchsite or chlorite inclusions

Basalt

Basalt

Diamond

Diamond (pure Carbon, C)