Basalt
Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
igneous
Category
Mineral Like Byproduct
Browse mineral like byproduct specimens identified by the Rock Identifier community.
Obsidian
Obsidian (Volcanic Glass, primarily SiO2)
igneous
Amethyst Quartz
Silicon Dioxide (SiO2) with iron impurities
mineral
Limonite (Iron Ore)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
mineral
Snowflake Obsidian
Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions
igneous
Desert Rose
Gypsum (variety Selenite) - CaSO4·2H2O
mineral
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)
sedimentary
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
sedimentary
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Igneous
Lepidolite
K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2
mineral
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Mineral (Sedimentary context)
Gneiss
Gneiss
metamorphic
Ironstone Concretion (Iron-rich Mudstone)
Siderite / Geothite concretion (FeCO3 / FeO(OH))
sedimentary
Amber
Succinite (Resin C10H16O)
mineral
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
mineral
Dyed Quartz Geode
Silicon Dioxide (SiO2) with artificial pigment
mineral
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Schist
Mica Schist
metamorphic
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Obsidian
Obsidian (Volcanic Glass)
igneous
Granitic Pegmatite with Schorl
Granitic Pegmatite (Schorl: NaFe3Al6(Si6O18)(BO3)3(OH)3OH)
igneous
Kimberlite with Diamond
Kimberlite (Diamond formula: C)
igneous
Mica Schist with Quartz
Mica-Quartz Schist (Muscovite subclass)
metamorphic
Sandstone (Ferruginous)
Arenite (with Goethite/Limonite cement)
sedimentary
Quartz (specifically Clear Quartz or Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Limonite (Iron Stone/Gossen)
Limonite (FeO(OH)·nH2O)
mineral
Epidote
Epidote (Ca2(Al,Fe)3(SiO4)3(OH))
mineral
Conglomerate (River Rock)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
metamorphic
Tree Agate
Dendritic Chalcedony (SiO2)
sedimentary
Sapphire (Raw/Rough)
Corundum (Al2O3)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
mineral
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
mineral
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Schorl (Black Tourmaline) in Matrix
Sodium Iron Aluminum Borosilicate Hydroxide (NaFe2+3Al6Si6O18(BO3)3(OH)3OH)
mineral
Shale
Laminated Mudstone
sedimentary
Sandstone
Arenite
sedimentary
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Sandstone
Arenite
sedimentary