Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material)

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Chert (Flint)

Microcrystalline quartz (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 principal composition)

Red Sandstone (Iron-rich)

Ferruginous Sandstone (SiO2 with Iron Oxides)

Fossilized Oyster Shell (Limestone/Coquina)

Crassostrea (Fossilized Bivalve), Calcium Carbonate (CaCO3)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Stichtite in Serpentine (Atlantasite)

Mg6Cr2CO3(OH)16·4H2O in Mg3Si2O5(OH)4

Chert (often called Flint or Jasper if reddish)

Microcrystalline Quartz (SiO2)

Peacock Ore

Bornite (Cu5FeS4) or Chalcopyrite (CuFeS2) with iridescent tarnish

Fancy Jasper

Silicon Dioxide (SiO2) with iron and organic inclusions

Pink Feldspar (Orthoclase)

Orthoclase Feldspar (KAlSi3O8)

Planet Earth

Gaia (Silicate Terrestrial Planet)

Milky Quartz

Silicon Dioxide (SiO2)

Moss Agate

Silicon Dioxide (SiO2) with Chlorite/Oxide inclusions

Chert (and/or River Pebble)

Microcrystalline quartz (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Glauconitic Sanstone (Glauconite)

Glauconite ((K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Sandstone (Ferruginous)

Arenite (with Goethite/Limonite cement)

Chert (Jasper variety)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Greenstone

Protolith of basalt, diabase, or gabbro; often contains minerals like chlorite, actinolite, and epidote

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Diamond (in a gold ring)

Diamond (pure carbon, C)

White Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Black Onyx

Cryptocrystalline Quartz (SiO2 with organic/iron impurities)

Red Sandstone

Arenite (Ferruginous Sandstone)

Petrified Wood

Silicified wood (primarily Silicon Dioxide, SiO2)

Quartz Sand Gravel

Silicon Dioxide (SiO2)

Dendritic Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe)

Pyrite in Shaly Matrix

Iron Sulfide (FeS2)

River Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

Moss Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe oxides)

Limestone Gravel

Calcium Carbonate (CaCO3)

Diamond

Diamond (pure carbon, C)

Moss Agate

Silicon Dioxide with inclusions (SiO2)

Silicon Carbide (Carborundum)

Moissanite (SiC)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide

Tiger's Eye

Tiger's Eye (SiO2 with crocidolite inclusions)