Tumbled jasper or rhyolitic porphyry
Silicic volcanic rock, likely rhyolite (quartz- and feldspar-rich), possibly jasperized
igneous
Category
Rock (Likely Sedimentary)
Browse rock (likely sedimentary) specimens identified by the Rock Identifier community.
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Yellow Quartz (Citrine Quartz Pebble)
Silicon Dioxide (SiO2)
mineral
Basalt with Iron Oxidation
Amygdaloidal Basalt (silicate rock primarily plagioclase, pyroxene, and olivine)
igneous
Chert (or Flint)
Chert (a cryptocrystalline variety of quartz, SiO2)
sedimentary
Tumbled serpentinite (likely antigorite-rich serpentine)
Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chromite, or brucite
metamorphic
Vesicular basalt (weathered volcanic rock)
Basalt, chiefly plagioclase feldspar, clinopyroxene, and possibly olivine/iron oxides
igneous
Shale
Sedimentary pelitic rock
sedimentary
River Stone (Basalt Porphyry)
Basalt (with possible olivine or plagioclase phenocrysts)
igneous
Quartz (likely Yellow/Orange variety, possibly Citrine or Chalcedony with iron staining)
Quartz (SiO₂)
Mineral
Purple fluorite-bearing matrix specimen
Fluorite (calcium fluoride, CaF₂), likely with quartz and host-rock minerals
mineral
Pink Granite
Phaneritic Felsic Igneous Rock
igneous
Basalt
Mafic Igneous Rock (composed primarily of pyroxene and calcium-rich plagioclase)
igneous
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
sedimentary
Pink Granite
Felsic intrusive igneous rock (Granite)
igneous
Pink Granite Boulder
Granite (Felsic Intrusive Igneous Rock)
igneous
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
igneous
Likely tumbled basalt or dark volcanic rock
Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides
igneous
Granite Pebble
Granite
igneous
Quartz Pebble
Crystalline Silicon Dioxide (SiO2)
sedimentary
Dyed Pink Agate
Silicon Dioxide (SiO2) - variety Chalcedony
mineral
Tumbled quartz-rich stone, likely milky quartz
Quartz (SiO₂), possibly iron-stained milky quartz or quartzite
mineral
Agatized Fossil or Chalcedony Nodule
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
sedimentary
Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
sedimentary
Quartz Grain / Sandstone Fragment
Silicon Dioxide (SiO2)
sedimentary
Orthoclase Feldspar
Orthoclase (KAlSi3O8)
Mineral
Garnet
Almandine/Pyrope Garnet (Silicate Mineral Group)
mineral
Iron-stained garnet-bearing rock, possibly almandine garnet
Garnet-group silicate, likely almandine (Fe₃Al₂Si₃O₁₂), in a quartz–iron-oxide matrix
mineral
Tumbled basalt (likely)
Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine
igneous
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Basalt with Plagioclase or Quartz Inclusion
Melanocratic Basalt with Porphyritic Inclusion
igneous
Chert / Jasper
Silicon Dioxide (SiO2)
sedimentary
Jasper
Silicon Dioxide (SiO2) - Opaque Chalcedony
sedimentary
Chert (Fossiliferous)
Silicon dioxide (SiO2)
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Milky quartz with dark host-rock inclusions
Quartz (SiO₂), likely in a granitic or metamorphic matrix
mineral
Yellow Chert (Chert / Jasper)
Silicon Dioxide (SiO2 / Microcrystalline Quartz)
sedimentary
Chert / Flint (River Pebble)
Cryptocrystalline Quartz (SiO2)
sedimentary
Pumice
Pumicite
igneous
Quartz Vein in Host Rock
Quartz (SiO2) in metamorphic host rock (likely schist or phyllite)
metamorphic
Tumbled brown quartzite or jasper
Quartzite (mostly SiO₂), possibly iron-rich jasper (microcrystalline quartz)
metamorphic
Granite
Phaneritic plutonic rock (High silica)
igneous
Weathered basaltic rock (probable basalt)
Basalt; fine-grained mafic silicate rock, commonly plagioclase + pyroxene ± olivine
igneous