Man Made (Synthetic Rock)

Chalk

Calcium carbonate (CaCO3)

Chalk

Calcium Carbonate (CaCO3)

Chert (Flint)

Silicon Dioxide (SiO2)

Limpets Shell / Fossil Specimen

Patellogastropoda (Class)

Dalmatian jasper

Orbicular rhyolite, commonly sold as Dalmatian jasper; quartz- and feldspar-rich volcanic rock with dark amphibole/biotite inclusions

Sandstone

Arenite (specifically sublithic or quartz arenite)

Red Sandstone

Quartz Arenite (iron-stained) / SiO2

Chalk

Carbonate rock (mainly CaCO3)

Faceted colorless gemstone, likely quartz or glass imitation

Most plausibly rock crystal (quartz, SiO₂); identity is uncertain because the photograph shows only intense facet reflections

Mica Schist

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

Fossiliferous Limestone with Crinoid Stem

Sedimentary Rock with Crinoidea Fossil

Basalt

Basalt (Mafic volcanic rock)

Granite

Phaneritic Felsic Igneous Rock

Natural Pearl

Calcium carbonate (primarily Aragonite and Conchiolin), CaCO3

Sandstone (Water-worn Cobble)

Arenite (SiO2 with CaCO3 or Fe2O3 cement)

Gemstone Ring

Various (Likely Glass, Cubic Zirconia, or assorted semi-precious stones)

Asphalt Chunk (with aggregate)

Bituminous concrete / Anthropogenic conglomerate

Blue slag glass / industrial glass fragment

Artificial silicate glass, composition variable; likely copper- or cobalt-colored furnace slag

Sandstone (Pebble)

Sandstone (SiO2 with matrix/cement)

Turquoise ring

Turquoise, hydrated copper–aluminum phosphate (CuAl₆(PO₄)₄(OH)₈·4H₂O)

Greenstone pebble

Greenstone (metamorphosed mafic rock, commonly altered basalt); exact identification requires testing

Coquina / Fossiliferous Limestone

Calcareous bioclastic sedimentary rock (CaCO3)

Aura Quartz (Anomalously Coated Quartz)

Silicon Dioxide (SiO2) treated with vaporized metals

Chert (and Agate/Chalcedony)

Microcrystalline Quartz (SiO2)

Sandstone

Arenite (SiO2 primarily)

Granite

Granite (Silicic Intrusive Igneous Rock)

Red glassy mineral specimen, likely synthetic ruby or red spinel

Most consistent with synthetic corundum (Al₂O₃, ruby) or synthetic spinel (MgAl₂O₄); exact identification requires testing

Colorless faceted gemstone, likely quartz (rock crystal)

Quartz, silicon dioxide (SiO₂); exact identification cannot be confirmed from the photograph

Red coral chip bracelet

Corallium spp.; skeleton composed primarily of calcium carbonate (aragonite)

Quartz Sandstone Pebble

Sandstone (SiO2 dominated)

Tumbled brown chalcedony or agate

Microcrystalline quartz (SiO₂), likely chalcedony; possibly iron-stained jasper or agate

Blue Dyed Agate

Cryptocrystalline Quartz (SiO2)

Chert Nodule

Microcrystalline Quartz (SiO2)

Pumice or vesicular volcanic tuff

Pumice: highly vesicular volcanic glass, chiefly rhyolitic to dacitic; possible tuff: lithified ash and pumice fragments

Pink Granite

Phaneritic Felsic Igneous Rock (composed of orthoclase, quartz, and plagioclase)

Sandstone

Arenite (primarily SiO2)

Brown chert (flint)

Microcrystalline quartz (SiO₂), varieties called chert or flint

Red faceted gemstone, likely synthetic ruby

Corundum (Al₂O₃), chromium-colored; possibly flame-fusion synthetic ruby

Ruby (Raw Corundum)

Al2O3 (Aluminum Oxide)

Clear gemstone earring (likely cubic zirconia)

Cubic zirconia (synthetic zirconium dioxide, ZrO₂); identification from the image is uncertain

Amber-set ring

Amber (fossilized plant resin; organic mineraloid), set in a metal ring

Clay Brick

Ceramic structural unit (Al2O3·2SiO2·2H2O as precursor)