Not A Rock (Man Made Origin)

Pearl

Calcium carbonate (CaCO3) + organic conchiolin

Sandstone

Arenite (SiO2 principal)

Quartz Pebble

Silicon Dioxide (SiO2)

Beach Pebble (Chalcedony / Chert)

Silicon Dioxide (SiO2)

Man-made Green Quartz (Lab-grown or Treated)

Silicon Dioxide (SiO2) with artificial coloration

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite

Quartzite (Metamorphic Quartz Sandstone)

Snowflake Obsidian

Volcanic glass with Cristobalite inclusions (70–75% SiO2)

Granodiorite with Quartz Veining

Granodiorite (containing Plagioclase Feldspar, Quartz, and Biotite/Hornblende) with Quartz (SiO2) veins

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Limestone

Calcareous sedimentary rock (CaCO3)

Lapis Lazuli

Lazurite-rich metamorphic rock

Polished blue calcite sphere (tentative identification)

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

Sandstone (specifically Arkose or Quartz Arenite)

Arenite (primarily SiO2 with possible Feldspar)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Granite

Felsic intrusive igneous rock

Red Jasper

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Lapis Lazuli

Na8[Al6Si6O24]S2 (Lazurite component), a rock composed primarily of Lazurite, Calcite, and Pyrite

Quartz Pebble

Silicon Dioxide (SiO2)

Chondrite Meteorite

Stone Meteorite (Chondrite)

Iron-Nickel Meteorite

Siderite (Fe, Ni)

Lapis Lazuli

Sodium aluminum silicate with sulfur (main component: Lazurite [(Na,Ca)8(AlSiO4)6(SO4,S,Cl)2])

Granite

Granite (Phaneritic Quartz-Feldspar intrusive rock)

Petoskey Stone

Hexagonaria percarinata (Fossilized Coral)

Banded Sandstone

Arenite with Liesegang banding

Ocean Jasper

Silicon Dioxide (SiO2) microcrystalline quartz aggregate with inclusions

Shungite

Carbonaceous rock (primarily amorphous carbon)

Pink Sapphire

Corundum (Al2O3 with trace Chromium and Iron)

Note regarding baguette production (not a rock)

Digital text image - Somali language

Granodiorite

Granodiorite

Diamond (in a gold ring)

Diamond (pure carbon, C)

Granite

Phaneritic Felsic Intrusive Igneous Rock

Pearl

Nacre (Aragonite and Conchiolin), CaCO3

Banded Chert (River Stone)

Silicon Dioxide (SiO2)

Granite

Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)

Chert (Chert / Flint)

Microcrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO₂)

Sandstone (likely Quartzose Sandstone)

Arenite

Likely blue glass or synthetic gemstone jewelry

Uncertain; possibly synthetic spinel, cubic zirconia, or blue glass

Diorite

Diorite (Plagioclase feldspar and amphibole/biotite)

Swirled Agate Bead

Silicon Dioxide (SiO2)

Ruby (in a ring setting)

Corundum (Al2O3:Cr)