Sapphire
Corundum (Al2O3)
Category
Browse synthetic or natural fiber specimens identified by the Rock Identifier community.
Sapphire
Corundum (Al2O3)
Red Jasper
Jasper (Silicate Mineral), SiO2 with Fe2O3 inclusions
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
Slag
Ferrous Slag (Siliceous industrial waste)
Sandstone (with Liesegang rings or joints)
Clastic Sedimentary Rock (primarily Quartz with Iron Oxide cement)
Rough Citrine Quartz
Silicon Dioxide (SiO2) with iron impurities
Connemara Marble
Ophiocalcite (Serpentinitic Marble)
Rough Topaz
Aluminum silicate fluoride hydroxide [Al2SiO4(F, OH)2]
Amethyst
Silicon Dioxide (SiO2)
Green Fluorite (Beaded)
Fluorite (Calcium Fluoride, CaF2)
Ironstone concretion / Limonitic Sandstone
Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)
K2 Jasper (K2 Granite)
Azulite in Granite (Quartz + Feldspar + Biotite + Azurite)
Diamond
Diamond (C)
Chert (often called Jasper or River Rock)
Chert (SiO2)
Collection of Minerals and Ores
Various (e.g., Uraninite (U3O8), Carbon (C), Native Gold (Au), Hematite (Fe2O3), Galena (PbS), etc.)
Pearl (Biogenic Mineral)
Calcium Carbonate (primarily Aragonite) with Conchiolin; CaCO3
Fulgurite (Sand-tube)
Fulgurite (Lechatelierite-rich fused sand)
Turquoise (possible Dyed Magnesite/Howlite)
CuAl6(PO4)4(OH)8·4H2O
Banded Chert / Flint
Silicon dioxide (SiO2)
Pearl (in a decorative hair comb setting)
Calcium carbonate (CaCO3) primarily as Aragonite, bonded with Conchiolin
Smoky Quartz
Silicon Dioxide (SiO2)
Rose Quartz
Silicon Dioxide (SiO2)
Quartz (Smoky/Milky variety)
Silicon Dioxide (SiO2)
Diamond
Carbon (C)
Pink Granite
Phaneritic intrusive igneous rock (Granite)
Banded Slag Glass (Leland Blue/Frankfort Green style)
Anthropogenic Glass Specimen (Amorphous Silicon Dioxide with impurities)
Blue Sapphire Crystal (Rough)
Corundum (Aluminum Oxide, Al2O3)
Yellow Quartz (Citrine or Quartzite Pebble)
Silicon Dioxide (SiO2)
Green Aventurine (Double-Terminated Wand)
Silicon Dioxide (SiO2) containing Fuchsite (Chromium-rich Muscovite Mica)
Diamond
Carbon (C)
Coquina
Coquina (Limestone variant)
Quartzite
Quartzite (SiO2 principal component)
Sandstone (Quartzose)
Arenite (SiO2 principal)
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
Aura Rose Quartz
SiO2 (Silicon Dioxide with Titanium/Gold coating)
Granite
Granite (Phaneritic intrusive igneous rock) - Composition: SiO2, Al2O3, K2O, Na2O
Jasper and Quartz River Cobble
Silicon Dioxide (SiO2) with Hematite inclusions
River Pebble (Gravel)
Clastic sedimentary rock (likely Siltstone or Mudstone pebble; SiO2 with various impurities)
Quartz Geode (Smoky Quartz)
Silicon Dioxide (SiO2)
Yellow Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Mahogany Obsidian
Obsidian with Hematite inclusions (SiO2 + Fe2O3)
Agate (specifically Chalcedony nodule)
Silicon Dioxide (SiO2)