Brachiopod Fossil (Spiriferid)
Order Spiriferida (Phylum Brachiopoda); mineralized as Calcite (CaCO3) or Chert (SiO2)
sedimentary (fossilized organic remain)
Category
Synthetic (Not A Natural Rock)
Browse synthetic (not a natural rock) specimens identified by the Rock Identifier community.
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Obsidian
Volcanic Glass
igneous
Clear Quartz Point
Silicon Dioxide (SiO2)
mineral
Shale
Shale (Fine-grained clastic sedimentary rock)
sedimentary
Sandstone (Ferruginous / River-worn Cobble)
Sandstone (SiO2 with iron oxide impurities)
sedimentary
Sandstone (Ferruginous)
Sandstone (SiO2 with iron oxide inclusions)
sedimentary
Sandstone (Ferruginous)
Arenite (with Hematite/Limonite cement)
sedimentary
Milky Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Sandstone (with Iron Staining)
Arenite (Silicon Dioxide, SiO2, often with iron oxides like Limonite)
sedimentary
Hag Stone (Sandstone with Boreholes)
Bored Sandstone (Sedimentary rock with lithophaga-style borings)
sedimentary
Azurite-Malachite (often a mixed specimen)
Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2(CO3)(OH)2. The specimen appears to be a natural mixture or intergrowth of these two minerals.
Mineral
Granite
Phaneritic Felsic Igneous Rock
igneous
Shale with Coprolite influence
Argillaceous sedimentary rock (Shale/Mudstone)
sedimentary
Opal
Hydrated silica (SiO2 "NH2O)
mineraloid
Sandstone Pebble
Arenite (primarily SiO2)
sedimentary
Orange Quartzite (or Quartz River Pebble)
Silicon Dioxide (SiO2) - Quartzite
metamorphic
Clear Quartz Crystal
Quartz (Silicon Dioxide, SiO2)
mineral
Sandstone (Ferruginous)
Arenite (SiO2 with Fe2O3 inclusions)
sedimentary
Sandstone (Quartzose)
Arenite (SiO2 principal)
sedimentary
Brecciated Jasper
SiO2 (Silicon Dioxide)
sedimentary
Sandstone (likely Quartzose Sandstone)
Arenite
sedimentary
Dyed Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
mineral
Goldstone (Red)
Aventurine Glass (SiO2 + Cu)
Synthetic Glass (Often categorized as a simulated mineral)
Mixed mineral and rock collection
Predominantly quartz varieties, including amethyst, plus likely calcite, feldspar, mica, and miscellaneous polished stones
mineral
Smoky Quartz
Smoky Quartz (Silicon Dioxide - SiO2)
mineral
Quartz-rich rock fragment, possibly granite or quartzite
Primarily quartz (SiO₂), with possible feldspar and iron-oxide staining
igneous or metamorphic
Smoky Quartz with Feldspar
Silicon Dioxide (SiO2) with Potassium Feldspar (KAlSi3O8)
mineral
Amethyst (Variety of Quartz)
Silicon Dioxide (SiO2) with iron impurities
mineral
Amethyst Quartz
Silicon Dioxide (SiO2) with iron impurities
mineral
Sandstone (likely Arkosic or Lithic)
Clastic Sedimentary Rock (SiO2 with accessory minerals)
sedimentary
Sandstone (Quartzose Sandstone / Feldspathic Sandstone)
SiO2 with minor impurities (Fe2O3, KAlSi3O8)
sedimentary
Granite
Phaneritic plutonic rock (Quartz, Feldspar, Mica)
igneous
Epidote (Unakite component) / Green Quartzite
Ca2(Al,Fe)3(SiO4)3(OH)
metamorphic
Conglomerate
Polymictic Conglomerate
sedimentary
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Amygdaloidal Basalt
Basalt (Igneous Volcanic Rock with secondary mineral infilling)
igneous
Sandstone (Quartz-rich)
Sandstone (SiO2 dominated)
sedimentary
Flint / Chert
Silicon Dioxide (SiO2)
sedimentary
Snakeskin Agate
Cryptocrystalline Quartz (SiO2)
mineral
Amethyst
SiO2 (Silicon Dioxide with Iron impurities)
mineral
Quartz (Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite
sedimentary