Not A Natural Rock (Man Made Composite)

Peacock Ore (Bornite or Iridescent Chalcopyrite)

Bornite (Cu5FeS4) or Chalcopyrite (CuFeS2) with oxidation

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Tumbled dark river pebble, probably basalt

Fine-grained mafic volcanic rock, most likely basalt; exact identification requires testing

Angel Skin Coral

Corallium rubrum / Corallium spp. (Calcium Carbonate, CaCO3)

Red Coral (Precious Coral)

Corallium rubrum (Calcium Carbonate, CaCO3)

Shale

Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)

Iron-rich slag or limonite-bearing rock

Hydrated iron oxides, chiefly limonite/goethite (FeO(OH)·nH₂O); possibly industrial iron slag

Turquoise in Matrix

CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)

Precious Red Coral

Corallium rubrum (Calcium Carbonate, CaCO3)

Red cabochon gemstone, likely carnelian

Carnelian: orange-red chalcedony, microcrystalline quartz (SiO₂)

Weathered brown stone, possibly basalt or iron-rich sedimentary rock

Indeterminate from photograph; likely fine-grained mafic rock (basalt) or ferruginous sandstone

Tumbled pale greenish stone, likely serpentine or altered limestone

Probable serpentine-group rock (antigorite/lizardite), possibly serpentinite; identification is visual only

Red Coral

Corallium rubrum

Granite

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

Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Black Onyx

Chalcedony (Silicon Dioxide, SiO2)

Shale creek bed

Shale (fine-grained clastic sedimentary rock)

Green Druzy Quartz (Prasiolite)

Silicon Dioxide (SiO2) with inclusions (typically Chlorite or Actinolite)

Banded Agate (Onyx type)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Tumbled turquoise

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

Shale

Shale (fine-grained clastic sedimentary rock)

Precious Coral

Corallium rubrum (Calcium carbonate with trace carotene)

Limonite (Yellow Ochre)

FeO(OH)·nH2O (Hydrous iron(III) oxide-hydroxide mixture)

Lapis Lazuli

Lazurite-dominant rock, (Na,Ca)8(AlSiO4)6(SO4,S,Cl)2

Black Onyx

Silicon dioxide (SiO2) - Chalcedony variety

Greenstone / serpentinized ultramafic rock (probable)

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible magnetite and talc

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

Smoky Quartz

Smoky Quartz (SiO ₂)

Black Tourmaline

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Rounded weathered pebble, likely sandstone or altered limestone

Indeterminate clastic carbonate/siliciclastic rock; exact identification requires a fresh surface and tests

Sandstone

Quartz Arenite (a common type of sandstone, given the appearance), Arkose, Greywacke (depending on mineralogy)

Limonite / Goethite Ironstone

FeO(OH)·nH2O (Hydrous iron oxide)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (likely a macrocrystalline variety like milky quartz or smoky quartz, given the appearance in the image)

Quartz (SiO₂ - Silicon Dioxide)

Amethyst

SiO2 (Silicon Dioxide with Iron impurities and natural radiation influence)

Sandstone

Sandstone (lithified arenite/wacke)

Quartzite

Quartzite

Sandstone

Arenite (general term for sandstone)

Ammonite Fossil

Ammonoidea

Possible tektite or dark volcanic rock fragment

Uncertain; likely natural silicate glass (tektite) or basalt