Man Made Rock Like Material

Chert (Flint)

Silicon Dioxide (SiO2)

Granodiorite

Phaneritic Plutonic Intermediate-Felsic Rock

Chipped Glass/Plastic Fragment

Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic

Granite

Granite (felsic intrusive igneous rock)

Granite

Phaneritic plutonic rock (SiO2 typically >69%)

Sandstone (Pebble)

Sandstone (SiO2 with matrix/cement)

Coquina

Coquina (Biogenic Limestone / CaCO3)

Sandstone

Arenite

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Dyed Crackle Quartz

Silicon Dioxide (SiO2) with synthetic dye

Chert (often called Flint or Jasper)

Microcrystalline Quartz (SiO2)

Sandstone

Arenite (SiO2 principal)

Dyed Dragon Vein Agate

Silicon Dioxide (SiO2) with artificial pigment

Diorite

Intermediate plutonic igneous rock

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Bauxite

Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))

Banded agate pendant (likely carnelian or brown-and-white chalcedony agate)

Agate, a banded variety of chalcedony; microcrystalline quartz, SiO₂, with iron-oxide coloration

Sandstone

Sedimentary Rock (Quartz arenite)

Coquina

Bioclastic Limestone (composed primarily of CaCO3)

Cobalt Glass Slug (Man-made Glass)

Amorphous Silica with Cobalt Oxide (SiO2 + CoO)

Granite

Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Coquina Limestone

Coquina (Biogenic Limestone)

Tumbled greenstone (likely serpentinite or green jasper)

Serpentinite, commonly dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄); exact identification requires testing

Polished blue calcite sphere (tentative identification)

Calcite, CaCO₃; blue color generally results from trace impurities or inclusions

Chert (Nodule)

Chert (Alpha-Quartz, SiO2)

Sandstone

Sandstone (SiO2-rich clastic sedimentary rock)

Likely iron-rich rock or weathered metallic mineral fragment

Uncertain; possibly limonite/goethite or iron-bearing slag

Sandstone

Sedimentary Clastic Rock (Quartzose Sandstone)

Petrified Wood

Silicified Wood (SiO2)

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Nacre (Mother of Pearl)

Nacre (Biogenic Aragonite/Calcite composite, CaCO3)

Granite

Granitoid (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8 + SiO2)

Terracotta (Man-made ceramic brick fragment)

Baked clay / High-iron ceramic (Silicate-based ceramic)

Chert (and associated river cobbles)

Silicon dioxide (SiO2)

Chert (often called Flint)

Chert (SiO2)

Diamond (in jewelry setting)

Carbon (C)

Sandstone (Quartzose)

Sandstone (SiO2 dominated)

Diamond (as set in a metal alloy ring)

Diamond (Pure Carbon, C)

Siltstone Pebble

Siltstone (composed of microscopic quartz and clay minerals)

Mica Schist

Mica Schist (principally Biotite/Muscovite, Quartz, and Feldspar)

Chert (often called Flint or Agate nodule)

Cryptocrystalline Quartz (SiO2)

Desert Rose (Baryte or Gypsum Rose)

Baryte (BaSO4) or Gypsum (CaSO4·2H2O)