Mineral Like (Natural Glass)

Turquoise

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

Mahogany Obsidian

Volcanic glass (high silica) with inclusions of Magnetite or Hematite

Slate

Foliated Metamorphic Rock (composed primarily of Quartz, Muscovite, and Illite)

Clear Quartz

Silicon Dioxide (SiO2)

Sandstone

Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite mica

Granite

Granite

Blue Dyed Agate Geode

Chalcedony (cryptocrystalline Quartz), SiO2

Obsidian

Volcanic Glass (SiO2)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Faceted blue gemstone, likely blue topaz or synthetic spinel

Topaz (Al₂SiO₄(F,OH)₂) or synthetic spinel (MgAl₂O₄); image insufficient for certainty

Vesicular Basalt

Extrusive mafic igneous rock

Tumbled blue-gray chalcedony (likely blue agate)

Chalcedony, microcrystalline quartz (SiO₂)

Opal

Hydrated silica (SiO2 "NH2O)

Obsidian

Volcanic Glass (SiO2)

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Black Obsidian

Obsidian (Volcanic Glass)

Limonite with Pyrite

Hydrated Iron Oxide Hydroxide, FeO(OH)·nH2O

Black Onyx

Silicon dioxide (SiO2) - Chalcedony variety

Blue Topaz

Al2SiO4(F,OH)2

Muscovite Mica

Muscovite, KAl2(AlSi3O10)(OH)2

Quartz (Clear/Milky)

Silicon Dioxide (SiO2)

Rose Quartz

Silicon Dioxide (SiO2)

Brown Chert

Cryptocrystalline Silica (SiO2)

Amethyst Quartz fragment

SiO2 (Silicon Dioxide with Iron impurities)

Clear Quartz

Silicon Dioxide (SiO2)

Ruby

Corundum (Al2O3 with Chromium impurities)

Granite

Intrusive Igneous Rock

Sandstone

Arenite

Satin Spar (Selenite)

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Porphyritic Basalt (Porphyry pebble)

Porphyritic Basalt / Amygdaloidal Basalt

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

Quartz (SiO₂ - Silicon Dioxide)

Red Coral (with Hematite and Black Pearl accents)

Corallium rubrum (Calcium Carbonate, CaCO3)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Flint (or Chert)

Silicon dioxide (Microcrystalline Quartz, $SiO_2$)

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Blue Quartz with Graphite/Tourmaline Inclusions

Silicon Dioxide (SiO2) with Carbon (C) or Schorl elements

Yellow Ocherous Siltstone (Limonitic Shale)

Limonitic Siltstone / Goethite-rich Sedimentary Rock

Quartzite

Quartzite (SiO2)

Aventurine Quartz

Silicon dioxide with inclusions (KAl2(AlSi3O10)(OH,F)2)

Blue Howlite (Dyed)

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Weathered pink granite fragment

Granite, chiefly quartz, potassium feldspar, and plagioclase feldspar with minor mica