Corundum (Sapphire/Ruby in Matrix)
Corundum (Al2O3)
Category
Browse synthetic or natural fiber specimens identified by the Rock Identifier community.
Corundum (Sapphire/Ruby in Matrix)
Corundum (Al2O3)
Magnetite
Magnetite (Fe3O4)
Rough Diamond
Diamond (C)
Tahitian Black Pearl
Biogenic Calcium Carbonate (Aragonite/Conchiolin Mixture), CaCO3
Pyrite in Matrix (Fool's Gold)
Iron Disulfide (FeS2)
Shale
Shale (clay-sized silicate minerals)
Quartz Heart or Arrowhead Shape
Silicon Dioxide (SiO2)
Aluminum Slag
Anthropogenic Aluminum (Al)
Citrine
Citrine (Silicon Dioxide, SiO2)
Amethyst (Tumbled)
Silicon Dioxide (SiO2) with iron impurities
Quartz (Smoky/Grey Variety)
Silicon Dioxide (SiO2)
Smoky Quartz
Smoky Quartz (SiO2)
Ventifact
Eolian Ventifact (often composed of basalt, chert, or quartzite)
Citrine
Silicon dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2) with aluminum impurities
Quartz (Smoky Quartz variant)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Smoky Quartz
SiO2 (Silicon Dioxide)
Amethyst
Silicon Dioxide with iron impurities (SiO2)
Cupronickel (on a 1981 Mexico 20 Pesos coin)
Copper-Nickel Alloy (Cu75Ni25)
Blue Dyed Agate Geode Slice
Chalcedony (Silicon Dioxide, SiO2) with artificial cobalt/iron-based dye
Citrine
Silicon Dioxide (SiO2) with Fe3+ impurities
Citrine Quartz
Silicon Dioxide (SiO2) with iron impurities
Citrine Quartz
Silicon Dioxide (SiO2)
Amber
Succinite (fossilized tree resin)
Citrine
Silicon Dioxide (SiO₂)
Smoky Quartz
Silicon Dioxide (SiO2)
Diamond
Native Carbon (C)
Sandstone (Ferruginous)
Sandstone (SiO2 with iron oxide inclusions)
Smoky Quartz
Quartz (Silicon Dioxide) - SiO2
Sandstone (Quartz Arenite)
Sandstone (SiO2 with possible mineral cements)
Chevron Amethyst
Silicon Dioxide (SiO2) with iron impurities
Conglomerate
Conglomerate (clastic sedimentary rock)
Sandstone (likely Quartzose Sandstone)
Clastic Sedimentary Rock (primarily SiO2)
Citrine
Silicon Dioxide (SiO2) with iron impurities
Sandstone (Ferruginous)
Clastic Sedimentary Rock (SiO2 with Fe2O3)
Strawberry Quartz
Silicon Dioxide (SiO2) with Hematite/Goethite inclusions
Citrine Quartz Sphere
Silicon Dioxide (SiO2)
Diamond
Carbon (C)
Sandstone
Arenite (typically SiO2 based)
Citrine Quartz
SiO2 (Silicon Dioxide with Iron impurities)
Tahitian Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3