Mahogany Obsidian
Obsidian (volcanic glass with Hematite/Magnetite inclusions)
Category
Browse sedimentary (chemically precipitated mineral) specimens identified by the Rock Identifier community.
Mahogany Obsidian
Obsidian (volcanic glass with Hematite/Magnetite inclusions)
Quartzite Pebble (with Iron Staining)
Quartzite (SiO2)
Quartzite
Quartzite (primarily SiO2)
Onyx
Onyx (a variety of Chalcedony, SiO₂)
Banded Agate (Polished Slice)
Chalcedony (cryptocrystalline Quartz), SiO2
Banded Agate
Cryptocrystalline Quartz (SiO2)
Agate
Banded Chalcedony (SiO2 - Silicon Dioxide)
Agate (translucent slice)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Quartz Veined Basalt
Mafic Volcanic Rock with Microcrystalline Quartz (SiO2)
Quartz pebble
Silicon Dioxide (SiO2)
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Quartz (Milky/Yellowish Pebble)
Silicon Dioxide (SiO2)
Goldstone (Red/Brown)
Aventurine Glass (SiO2 with Copper inclusions)
Citrine (Yellow Quartz)
Silicon Dioxide (SiO2)
Dyed Agate
Silicon Dioxide (SiO2) with artificial pigment
Ferruginous Quartz
Iron-stained Quartz (SiO2 with Fe2O3 impurities)
Gold Nugget
Native Gold (Au)
White Quartz (Tumbled)
Silicon Dioxide (SiO2)
Iron-Stained Quartz (Riverside Cobble)
Silicon Dioxide (SiO2) with Limonite/Hematite inclusions
White Agate (Tumbled)
Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony
Banded Agate (Brazilian Agate Slice)
Chalcedony (Silicon Dioxide / SiO2)
Agate
Silicon Dioxide (SiO2) - Chalcedony variety
Jasper and Basalt Mix (Dark Chert/Basalt River Pebble)
Silicon Dioxide (SiO2) or Mafic extrusive igneous rock
Fluorite (often referred to casually as 'Fluorspar' in industrial contexts)
Fluorite (CaF2)
Quartz
Quartz (SiO2 - Silicon Dioxide)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Blue Goldstone
Aventurine Glass (Silicon Dioxide infused with Cobalt/Copper)
General Rock and Mineral Collection (Center: Angelite / Blue Anhydrite)
Anhydrite (Calcium Sulfate, CaSO4)
Quartzite and Chert
Silicon Dioxide (SiO2)
Tiger's Eye (Rough)
Pseudomorph of Quartz after Crocidolite (SiO2 with Iron inclusions)
Slag Glass
Amorphous Silica / Glass Slag
Granite (specifically Rapakivi Granite)
Phaneritic Felsic Igneous Rock (Granite)
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
Diamond
Carbon (C), specifically in an isometric crystal system.
Pink Dyed Agate
Chalcedony (SiO2) with artificial dyes
Dzi Bead (Agate)
Chalcedony (cryptocrystalline variety of Quartz), SiO2
Quartz Pebble
Silicon Dioxide (SiO2)
Basalt with Iron Oxidation
Aphanitic Mafic Igneous Rock (composed primarily of Plagioclase and Pyroxene)
Pyrite
Iron Sulfide (FeS2)
Apatite
Apatite group mineral (e.g., Fluorapatite - Ca5(PO4)3F, Chlorapatite - Ca5(PO4)3Cl, Hydroxylapatite - Ca5(PO4)3(OH))
Chalcedony
Chalcedony (SiO₂)
Nephrite Jade
Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)