Igneous Rock (Volcanic Glass)

Diorite (Dalmatian Stone variant)

Phaneritic Plutonic Igneous Rock (Medium to Fine-grained Diorite)

Pyrite-bearing Rock

Iron Sulfide (FeS2) associated with host rock

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Weathered granite or granitic gneiss pebble

Granite, primarily quartz, feldspar, and mica; possibly weakly foliated gneiss

Quartz Geode

Silicon Dioxide (SiO2) in Geodic habit

Basalt

Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)

Yellow Chalcedony / Yellow Agate

Silicon Dioxide (SiO2)

Basalt Pebble

Basalt

Black Obsidian

Volcanic Glass (Amorphous Silicon Dioxide, SiO2)

Mahogany Obsidian

Volcanic glass (SiO2 with Hematite or Magnetite inclusions)

Basalt Pebble

Basalt

Agate

Agatized Chalcedony (SiO2)

Druzy Quartz (on Chalcedony/Agate base)

Silicon Dioxide (SiO2)

Pink Granite

Phaneritic Felsic Igneous Rock (Granite)

Basalt

Basalt (containing plagioclase, pyroxene, and olivine)

Black Obsidian

Volcanic Glass (Amorphous Silicon Dioxide, SiO2)

Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Snowflake Obsidian

Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions

Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Basalt (River Pebble)

Basalt (Mafic Extrusive Igneous Rock)

Muscovite Mica

Muscovite KAl2(AlSi3O10)(OH)2

Jasper

Silicon Dioxide (SiO2) with impurities, Microcrystalline Quartz

Amethyst

Amethyst (Silicon Dioxide, SiO2 with Iron impurities)

Milky Quartz

Silicon Dioxide (SiO2)

Scoria (Lava Rock)

Vesicular Basalt / Scoria

Obsidian (likely blue-sheen or coated obsidian)

Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, noncrystalline)

Exposed granitic bedrock

Granite, likely a foliated or weathered granitoid (quartz–feldspar–mica assemblage)

Quartz Veined Basalt Pebble

Amygdaloidal Basalt with Quartz (SiO2) veining

Clear Quartz / Rock Crystal

Silicon Dioxide (SiO2)

Decorative polished pebbles

Likely mixed quartz-rich lithologies, including quartzite, jasper, and/or basalt

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Black Obsidian

Volcanic Glass (Silicon Dioxide with impurities)

Black Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Quartz Pebble (Iron-Stained Quartz)

Silicon Dioxide (SiO2) with Hematite/Limonite inclusion

Basalt with Quartz Vein

Basalt (fine-grained mafic igneous rock) with crystalline Quartz (SiO2)

Granite with Quartz Vein

Phaneritic Felsic Igneous Rock (composed of Quartz [SiO2], Feldspar, and Mica)

Basalt

Mafic Volcanic Rock (composed mainly of Plagioclase, Pyroxene, and Olivine)

Diorite

Diorite (intermediate intrusive igneous rock)

Red Jasper (Brecciated Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions