Basalt
Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)
igneous
Category
Mineral Based Composite
Browse mineral based composite specimens identified by the Rock Identifier community.
Diorite
Phaneritic Intermediate Igneous Rock
igneous
Granite (Alkali-feldspar rich)
Phaneritic Felsic Igneous Rock (Major components: KAlSi3O8, SiO2)
igneous
Basalt
Basalt (composition predominately plagioclase feldspar and pyroxene)
igneous
Conglomerate (River Rock)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Ironstone (Limonitic Sandstone)
Ferruginous Sandstone (rich in Limonite: FeO(OH)·nH2O)
sedimentary
Amygdaloidal Basalt
Amygdaloidal Basalt (Host rock) with Quartz or Calcite amygdules
igneous
Quartz Druzy on Agate (River Cobble)
Silicon Dioxide (SiO2)
Mineral / Sedimentary (often associated with volcanic hosts)
Chert (Field Stone/Jasper variety)
Microcrystalline Quartz (SiO2)
sedimentary
Lepidolite
K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2 (Lepidolite - Lithium-rich Mica)
mineral
Asphalt (Bituminous Concrete)
Bituminous mix / Anthropogenic conglomerate
man-made composite (lithified equivalent of sedimentary)
Labradorite
(Ca, Na)(Al, Si)4O8 (Calcium Sodium Aluminum Silicate)
mineral
Aquamarine with Quartz
Beryl (Be3Al2Si6O18) with Quartz (SiO2)
mineral
Dendritic Agate
Chalcedony (SiO2) with manganese/iron oxide inclusions
mineral
Muscovite Mica
Muscovite - KAl2(AlSi3O10)(OH)2
mineral
Mica (Muscovite)
Potassium aluminum silicate - KAl2(AlSi3O10)(OH)2
mineral
Slate with Iron Staining
Low-grade Metamorphic Mudstone (Slate)
metamorphic
Gastropod Steinkern (Fossil Snail Internal Mold)
Class Gastropoda (Internal Mold)
sedimentary
Schist (Garnet-Mica Schist)
Garnet-Mica Schist (X-Y)3Z2(SiO4)3
metamorphic
Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
mineral
Basalt with Magnetite inclusions
Basalt (Mafic silicate rock) potentially containing Magnetite (Fe3O4)
igneous
Granite
Granite (Felsic Intrusive Igneous Rock)
igneous
Granite
Phaneritic plutonic rock (Quartz, Feldspar, Mica)
igneous
Granite
Granite (composed primarily of Quartz SiO2, Orthoclase KAlSi3O8, and Plagioclase NaAlSi3O8 to CaAl2Si2O8)
Igneous
Schist
Mica Schist
metamorphic
Conglomerate (River Rock Aggregate)
Conglomerate (Lithic-clast conglomerate)
sedimentary
Chert (variations include Chalcedony and Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
White Quartz Pebble
Silicon Dioxide (SiO2)
mineral
River Pebble (Likely Chert or Fine-Grained Sandstone/Quartzite)
Siliciclastic clast (likely Chert or Quartzarenite/Quartzite pebble)
Sedimentary
Pink Granite
Phaneritic Plutonic Felsic Igneous Rock (Granite)
igneous
Sandstone (Quartz-rich Pebble)
Arenite (primarily SiO2)
sedimentary
Granodiorite Pebble
Granodiorite
igneous
Granite
Granite (Phaneritic Quartz-Feldspar Rock)
igneous
Snowflake Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)
igneous
Ferruginous Sandstone (with possible trace fossils)
Arenite with Iron-Oxide Cement (SiO2 with Fe2O3)
sedimentary
Sandstone
Arenite (Siliclastic sedimentary rock, primarily SiO2)
sedimentary
Diorite
Intermediate plutonic igneous rock
Igneous
Man-made Jewelry Charm (Enameled Metal)
Not a natural mineral; composed of base metal alloy (likely zinc or brass) and epoxy resin/enamel.
Synthetic / Manufactured Artifact
Dalmatian Stone
Dalmatian Jasper (Aplitic Rock)
igneous
Chert (specifically Jasper/Flint pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Diorite
Diorite (Intermediate plutonic rock)
igneous
Granite
Phaneritic Plutonic Rock (Granite)
igneous