Mineral (Silicate Replaced Organic Material)

Banded Chert

Cryptocrystalline Quartz (SiO2)

Asphalt Concrete (Bituminous Concrete)

Bituminous aggregate

Sandstone

Clastic sedimentary rock (primarily Quartz and Feldspar)

Sandstone

Arenite (composed primarily of SiO2)

Serpentinite

Serpentinite (complex silicate mineral group (Mg,Fe)3Si2O5(OH)4)

Gold and Silver (Metal Components of an Antique Pocket Watch)

Native Gold (Au) and Native Silver (Ag)

Jade

Jadeite or Nephrite

Dendritic Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with inclusions

Jasper with Manganese Dendrites

Silicon Dioxide (SiO2) with Oxide Mineral Inclusions

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Sunstone

(Ca,Na)(Al,Si)4O8 (Oligoclase or Andesine)

Amazonite

Microcline (KAlSi3O8) with trace lead (Pb)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Red Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Sandstone (Quartzite-rich)

Clastic Sedimentary Rock (primarily SiO2)

Moonstone

Adularia or Orthoclase (KAlSi3O8) or Albite (NaAlSi3O8), specifically with lamellar exsolution of albite and orthoclase.

Sandstone (likely Arkosic)

Clastic Sedimentary Rock (primarily SiO2 with Feldspar)

Sandstone

Arenite (primarily SiO2)

Glauconitic Sandstone (Greensand)

Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)

Chert (White Chert)

Silicon Dioxide (SiO2)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily Quartz with Limonite/Goethite staining)

Blue Goldstone

Man-made glass with crystalline copper/cobalt inclusions

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2)

Not a geological specimen

N/A (man-made object)

Sandstone

Clastic Sedimentary Rock (composed primarily of Quartz: SiO2)

Biotite Schist (likely)

Biotite Schist (rock), Biotite (mineral)

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Snowflake Obsidian

Obsidian with Cristobalite inclusions (Amorphous SiO2 + SiO2 inclusions)

Chert (specifically Tan Chert)

Chert (SiO2)

Obsidian

Obsidian (Volcanic Glass; SiO2 content > 70%)

Chert (Yellow or Tan Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Beryl (Emerald Variety)

Beryllium aluminum silicate (Be3Al2(SiO3)6) with chromium/vanadium traces

Zinc Ore (Sphalerite in Matrix)

Sphalerite (Zn,Fe)S within a carbonate or silicate host rock

Shale

Fissile Mudstone (Shale)

Ocean Jasper Mushroom

Orbicular Jasper (Silicon Dioxide, SiO2 mixed with various impurities)

Grey Chalcedony (Tumbled)

Chalcedony (SiO2)

Nephrite Jade

Nephrite (a variety of the mineral actinolite within the amphibole group); Chemical Formula: Ca2(Mg,Fe)5Si8O22(OH)2

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (primarily SiO2)

Sandstone (Ferruginous)

Arenite with Iron Oxides

Sandstone

Arenite (SiO2 principal composition)