Chert (Green and Black Jasper variant)
Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Synthetic (Not A Natural Rock)
Browse synthetic (not a natural rock) specimens identified by the Rock Identifier community.
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Granite
Phaneritic intrusive igneous rock
igneous
Scoria (Lava Rock)
Scoria (Extrusive Igneous Rock)
igneous
Quartzite
Quartzite (SiO2)
metamorphic
Herkimer Diamond
Quartz (SiO2)
mineral
Weathered porphyritic volcanic rock (likely andesite or basalt)
Aphanitic to porphyritic andesite–basalt; composition commonly plagioclase, pyroxene, and minor iron oxides
igneous
Amethyst Geodes
Silicon Dioxide (Quartz with Iron impurities), SiO2
mineral
Emerald in Host Rock
Beryl (Be3Al2Si6O18) containing Chromium and/or Vanadium
mineral
Amethyst
Crystalline Silicon Dioxide with iron impurities (SiO2)
gemstone
Clear Quartz
SiO2 (Silicon Dioxide)
mineral
Sandstone
Arenite (lithic or quartz sandstone)
sedimentary
Granite
Phaneritic plutonic rock (Quartz, Feldspar, Mica)
igneous
Slate
Slate (Low-grade foliated metamorphic rock)
metamorphic
Basalt Pebble
Basalt
igneous
Pumice
Pumice (Silicic volcanic glass with vesicular structure)
igneous
Silty Shale
Silty Shale (Fissile Sedimentary Rock)
sedimentary
Picture Jasper
Silicified sedimentary or volcanic rock (primarily SiO2)
sedimentary
Vesicular volcanic rock, likely weathered pumice or scoria
Pumice/scoria; predominantly volcanic glass and feldspar, with possible iron oxides
igneous
Agate and Amethyst (Quartz variants)
Silicon Dioxide (SiO2) - Microcrystalline Quartz and Crystalline Quartz
mineral
Green Tiger's Eye
Silicified Crocidolite (Quartz variety, SiO2)
metamorphic
Quartzite Pebble
Quartzite (SiO2-rich metamorphic rock)
metamorphic
Sapphire
Corundum (Al2O3)
mineral
Quartz (Milky/Smoky Quartz)
Silicon Dioxide (SiO2)
mineral
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (SiO2) with metallic oxide impurities
mineraloid
Quartzite
Quartzite (SiO2)
metamorphic
Shale
Fissile mudstone (primarily clay minerals and silt-sized quartz)
sedimentary
Dalmatian jasper
Orbicular microcrystalline quartz rock, commonly rhyolitic or volcanic-feldspar matrix with black arfvedsonite/alkali-amphibole inclusions
igneous
Basalt Pebble
Basalt (Mafic Extrusive Igneous Rock)
igneous
Likely basaltic rock fragment
Fine-grained mafic igneous rock, probably basalt (plagioclase–pyroxene ± olivine)
igneous
Rough Emerald/Green Beryl
Beryl (Be3Al2(SiO3)6) with trace amounts of Chromium or Vanadium
mineral
Banded Chert
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
igneous
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
igneous
Rounded river or beach pebble
Likely quartz-rich sandstone or quartzite; exact identification requires a close-grained view and hardness test
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Pumice
Pumice (Amorphous volcanic glass)
igneous
Granitoid (Granite/Granodiorite)
Plutonic igneous rock (variable composition, primarily SiO2)
igneous
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Yellow Chert (Yellow Jasper)
Silicon Dioxide (SiO2)
sedimentary
River Cobble (Diorite or Meta-volcanic with Quartz Veining)
Diorite (with SiO2 quartz veins)
igneous
Quartzite
Quartzite (composed primarily of silica, SiO2)
metamorphic
Smoky Quartz
Silicon Dioxide (SiO2)
mineral