River Siltstone / Mudstone Pebble
Siltstone (composed of mixed silicate and carbonate minerals)
sedimentary
Category
Organic (Non Geological)
Browse organic (non geological) specimens identified by the Rock Identifier community.
Snowflake Obsidian
Spherulitic Obsidian (Amorphous volcanic glass with Phenocrysts of Cristobalite)
igneous
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous
Obsidian
Volcanic Glass (70% or more SiO2)
igneous
Anthracite Coal
Anthracite
metamorphic
Banded Chert (River Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2)
igneous
Zebra Rock (Zebra Stone / Ribbon Stone)
Siltstone with Ferruginous Banding (Primarily Quartz, Kaolinite, and Hematite)
sedimentary
Opalite
Opalescent Glass (SiO2 + coloring agents)
Mineral (Synthetic/Man-made)
Chert (Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Moss Agate
Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions
mineral
Gold Ore (in Quartz/Sulfide matrix)
Native Gold (Au) in Quartz (SiO2) and Pyrite (FeS2)
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Acrylic or Resin (Synthetic Imitation)
Polymethyl Methacrylate (PMMA) or Polyepoxide
Synthetic/Man-made Polymer
Obsidian
Volcanic Glass (SiO2)
igneous
Fossiliferous Limestone (with Crinoids)
CaCO3 (Calcium Carbonate)
sedimentary
Snowflake Obsidian
Volcanic glass containing Cristobalite (SiO2)
igneous
Fossilized Coral
Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Quartz with Mica inclusions (Gold-colored Mica)
Silicon Dioxide (SiO2) with Potassium Aluminum Silicate (Phlogopite/Muscovite) inclusions
Mineral
Chert (Jasper-like Silicate)
Microcrystalline quartz (SiO2)
sedimentary
Chert (often called Flint or Jasper)
Silicon Dioxide (SiO2)
sedimentary
Jasper (specifically a banded or dark variety)
Silicon Dioxide (SiO2) with impurities
sedimentary
Chert (variations include Flint/Novaculite)
Chert (formula: SiO2)
sedimentary
Chert (specifically Flint or Gray Chalcedony)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (often called Flint or River Rock)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Flint Pebble)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Moqui Marbles
Iron Oxide Concretion (Hematite/Goethite)
sedimentary
Obsidian
Obsidian (Volcanic glass), 70-75% SiO2
igneous
Amber
Succinite (C10H16O)
mineraloid
Fossiliferous Chert (with Fossil Shells)
Silicon Dioxide (SiO2) with biogenic inclusions
sedimentary
Cullet Glass (Man-made Glass Slag)
Amorphous Silica (SiO2) with chemical additives
Mineraloid
Blue Goldstone
Aventurine Glass (Silicon Dioxide infused with Cobalt/Copper)
Synthetic (Man-made Glass)
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Quartzite with Garnet
Garnetiferous Quartzite (SiO2 + X3Y2(SiO4)3)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary