Man Made Glass (Not A Natural Rock Or Mineral)

Sandstone

Arenite (composed primarily of SiO2)

Druzy Quartz on Milky Quartz

Silicon Dioxide (SiO2)

Bismuth

Bismuth (Bi)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Chalcedony/Flint)

Silicon Dioxide (SiO2)

Ironstone (Limonitic Shale)

Ferruginous Siltstone / Goethite-rich Sedimentary Rock

Smoky Quartz

Silicon Dioxide (SiO2)

Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)

Quartz (Milky/Vein Quartz)

Silicon Dioxide (SiO2)

Orange Quartzite / Carnelian Agate

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Black Tourmaline

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

Smoky Quartz

Silicon Dioxide (SiO2)

Sandstone (Red)

Arenite (primarily Quartz, SiO2, with Iron Oxide cement)

Grey Slate

Foliated Metamorphic Rock (formed by low-grade regional metamorphism of shale or mudstone)

Rose Quartz

Silicon Dioxide (SiO2)

Obsidian

Obsidian (Volcanic Glass, complex silicate)

Amethyst

SiO2 (Silicon Dioxide with iron impurities)

Blue Chalcedony

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Carnelian Agate Nodule

Silicon Dioxide (SiO2) - Carnelian Chalcedony

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Pink Granite

Phaneritic Plutonic Felsic Rock (Granite)

Amber (specifically Cherry Amber)

Succinite (with the chemical formula C10H16O)

Yellow Quartzite (River Pebble)

Quartzite (primarily Silicon Dioxide, SiO2)

Sandstone (specifically Red Sandstone)

Arenite (SiO2 with Iron Oxide)

Amethyst Quartz

Silicon Dioxide (SiO2) with iron impurities

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Red Quartz (Druzy)

Silicon Dioxide (SiO2) with Hematite inclusions

Sandstone (likely Arkose or Quartz Sandstone)

Arenite (SiO2 principal component)

Milky Quartz

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Sandstone (Ferruginous)

Ferruginous Sandstone (SiO2 with Fe2O3)

Rose Quartz

Quartz (SiO₂), specifically a variety of Quartz

Petrified Wood

Silicified Wood (SiO2)

Ferruginous Quartz Cobble

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Quartz Vein Rock

Silicon Dioxide (SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Jasper

Jasper (SiO2 plus impurities)

Ruby (Corundum)

Corundum (Aluminum Oxide with Chromium), Al2O3:Cr

Ruby (Corundum)

Aluminum Oxide (Al2O3) with Chromium traces

Tiger's Eye (often misinterpreted as Gold Ore in this context)

Pseudomorph of Quartz after Crocidolite (SiO2)