Igneous, Specifically Volcanic

Weathered Volcanic Rock (possibly Rhyolite or Andesite Pebble)

Volcanic rock (e.g., Rhyolite or Andesite, specific identification would require thin section analysis or chemical assay). Mineral composition: Primarily feldspars (orthoclase and/or plagioclase), quartz (in rhyolite), micas, amphiboles, and sometimes pyroxenes.

Porphyritic Rhyolite

Porphyritic Rhyolite (SiO2)

Carnelian

Cryptocrystalline Quartz (SiO2)

Basalt

Basalt (Mafic volcanic rock)

Amethyst (Rough)

Silicon Dioxide with iron impurities (SiO2)

Quartz Druzy (on Geode Fragments)

Silicon Dioxide (SiO2)

Snowflake Obsidian

Obsidian with Cristobalite inclusions

Obsidian

Volcanic Glass (SiO2 + minor impurities)

Amygdaloidal Basalt

Amygdaloidal Basalt

Blue Lace Agate (Polished Point)

Silicon Dioxide (SiO2)

Dalmatian Jasper

Peralkaline Quartz-Feldspar Porphyry with Arfvedsonite

Polished Basalt

Basalt (Mafic volcanic rock)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with impurities of iron)

Dalmation Jasper (or Dalmation Stone)

Dalmation Stone (composed of Perthite, Quartz, and Arfvedsonite)

Bumblebee Jasper

Fossiliferous Volcanic Rock (composed of Calcium Carbonate, Manganese Oxides, and Arsenic Sulfides)

Dalmatian Jasper

Peralkaline Feldspar Diorite/Rhyolite

Carnelian

Carnelian (SiO2)

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2)

Banded Agate

Cryptocrystalline Quartz (SiO2)

Jasper Agate

Silicon dioxide (SiO2)

Dalmatian Stone

Dalmatian Jasper (Aphanitic Igneous Rock with Arfvedsonite inclusions)

Bumblebee Jasper

Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)

Moonstone (Green Moonstone / Garnierite)

Potassium Aluminum Silicate (KAlSi3O8) with inclusions of Garnierite

Blue Lace Agate (Chert/Chalcedony)

Silicon dioxide (SiO2)

Basalt with Magnetite

Crystalline Basalt (Primarily Plagioclase and Pyroxene) with Magnetite (Fe3O4)

Mahogany Obsidian

Obsidian (Volcanic Glass) with Hematite or Magnetite inclusions, SiO2 (Silicon Dioxide)

Amygdaloidal Basalt with Epidote/Chlorite

Basalt (containing (Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH)))

Basalt

Basalt (composition of plagioclase feldspar and pyroxene)

Green Porphyry (Flowerstone)

Porphyritic Andesite or Basalt

Mahogany Obsidian

Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2

Peridotite (Dunite)

Peridotite (comprising mainly Olivine)

Mahogany Obsidian Arrowhead

Obsidian (volcanic glass) with Hematite inclusions

Blue Lace Agate

Chalcedony (SiO2) with trace minerals

Basalt with Vesicle/Vug

Basalt (Aphanitic Mafic Igneous Rock)

Crazy Lace Agate

Chalcedony (Silicon Dioxide, SiO2)

Yellow Chalcedony (Agate)

Silicon Dioxide (SiO2)

Obsidian (Tumbled Apache Tear)

Volcanic Glass (SiO2)

Chalcedony (specifically Agate and Carnelian variety)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Apache Tear

Obsidian (Hydrated Volcanic Glass)

Apache Tear

Hydrated Obsidian (Natural Volcanic Glass)

Greenstone Porphyry

Porphyritic Metavolcanic Rock

Yellow Agate

Agate (Varietal form of Chalcedony/Quartz, SiO2)