Granodiorite
Granodiorite (phaneritic intrusive igneous rock)
igneous
Category
Igneous Rock (Volcanic Glass)
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
Quartz Geode
Silicon Dioxide (SiO2) in Host Rock
sedimentary
Granite (with Muscovite Mica)
Phaneritic Felsic Igneous Rock (primarily Quartz SiO2, K-Feldspar KAlSi3O8, and Muscovite KAl2(AlSi3O10)(OH)2)
igneous
Ocean Jasper
Spherulitic Chalcedony (SiO2)
sedimentary
Banded Agate
Chalcedony / Silicon Dioxide (SiO2)
mineral
Agate (specifically, a slice of a Blue Lace or Chalcedony Agate nodule)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Chert (Yellow/Tan Variety)
Chert (SiO2)
sedimentary
Agate
Silicon dioxide (SiO2)
mineral
Geode (Unopened)
Silicon Dioxide (SiO2) in sedimentary vugs
sedimentary
Blue Chalcedony
Silicon Dioxide (SiO2)
mineral
Agate with Druzy Quartz
Silicon Dioxide (SiO2)
mineral
Yellow Chert or Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Rock Crystal Quartz
Quartz (SiO₂)
Mineral
Graywacke
Graywacke
sedimentary
Shatter Cone
Impactite (Shatter Cone texture)
metamorphic
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
mineral
Pebble (likely a type of sandstone or quartzite pebble)
Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.
Sedimentary rock
Epidote (or Epidote-rich rock)
Epidote. Mineral formula: Ca2(Al,Fe)3(SiO4)3(OH).
Mineral, often found in metamorphic rocks but also in sedimentary and igneous rocks
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with mineral inclusions
Mineral/Mineraloid within a rock matrix
River Rock (Basalt)
Aphanitic Basaltic Rock
igneous
Granite
Granite (Felsic Intrusive)
igneous
Granite
Phaneritic Felsic Intrusive Igneous Rock
igneous
Quartz Geode (with Agate banding)
Silicon Dioxide (SiO2)
Sedimentary or Igneous (secondary formation)
Sandstone (Ferruginous)
Arenite (SiO2 with iron oxide impurities)
sedimentary
Sandstone
Sandstone (Sedimentary rock composed of silicate grains)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Basalt
Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)
igneous
Yellow Agate
Silicon Dioxide (SiO2)
mineral
Olivine in Basalt matrix
Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)
igneous
Unakite or Epidosite
Epidosite (Mineral composition: Epidote, Feldspar, and Quartz)
metamorphic
Quartzite with Hematite staining
Quartzite (SiO2) with iron oxide inclusions
metamorphic
Olivine (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4
Mineral
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Orca Agate (Chalcedony)
Silicon Dioxide (SiO2) with inclusions
mineral
Geode (Chert or Quartz Nodule)
Silicon Dioxide (SiO2)
sedimentary
Olivine (often within Peridotite)
Magnesium iron silicate, (Mg,Fe)2SiO4
mineral
Scoria
Vesicular Basalt / Scoria
igneous
Epidote-bearing Granite (Unakite-like)
Epidotized Granite
igneous
Pink Granite
Phaneritic Plutonic Felsic Igneous Rock (Granite)
igneous
Granite
Granitoid (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8 + SiO2)
igneous