Porphyritic Igneous Rock / Rhyolite Porphyry
Porphyritic volcanic rock
igneous
Category
Mineral, Often A Rock Given Its Aggregate Nature
Browse mineral, often a rock given its aggregate nature specimens identified by the Rock Identifier community.
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Banded Gneiss (with possible weathered sulfide or iron staining)
Gneiss, potentially with iron oxide/hydroxide staining (e.g., limonite) or weathered sulfides
Metamorphic
Jasper
Silicon dioxide (SiO2) with impurities
sedimentary
Sandstone (Water-worn pebble)
Arenite (primarily SiO2)
sedimentary
Goldstone
Aventurine Glass (Man-made)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Asphalt Concrete (Bituminous Conglomerate)
Anthropogenic Bituminous Conglomerate
sedimentary
Picture Jasper
SiO2
Mineral/Sedimentary
Banded Agate (specifically Carnelian Agate)
Silicon Dioxide (SiO2) - Chalcedony variety
mineral
Conglomerate
Conglomerate rock (detrital sedimentary)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Black Tourmaline (Schorl)
NaFe3+3Al6(BO3)3Si6O18(OH)4
mineral
Limestone
Limestone (Calcium Carbonate, CaCO3)
Sedimentary
Milky Quartz
Crystalline Silicon Dioxide (SiO2)
mineral
Chert (and Fossiliferous Limestone)
Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)
sedimentary
Goldstone
Aventurine Glass (SiO2 + Cu small inclusions)
man-made glass mineral simulant
Pyrite in Matrix (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Terrazzo (Synthetic Composite Rock)
Cementitious or Epoxy Resin-bound Aggregates
Man-made metamorphic-style composite
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Agate (Chalcedony)
Silicon Dioxide (SiO2)
mineral
Jasper Beads
Microcrystalline Quartz (SiO2)
sedimentary
Gold in Matrix
Native Gold (Au)
mineral
Blue Quartz
Silicon Dioxide (SiO2) with inclusions
mineral
Asphalt Chunk
Asphalt concrete
man-made composite
Opalite
Synthetic Opalised Glass
mineral
Black Tourmaline (Tumbled)
Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)
mineral
Sandstone
Arenite (primarily Quartz Arenite)
sedimentary
Sandstone pebble
Clastic sedimentary rock (primarily SiO2)
sedimentary
Siltstone with Fossil Cast
Sedimentary Rock (Siltstone / Fine-grained Sandstone)
sedimentary
Quartz (likely Clear Quartz or Rock Crystal)
Quartz (SiO2)
Mineral
Jasper
Jasper (Silica/Silicon Dioxide, SiO2)
sedimentary
Chrysocolla
Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Dyed Blue Agate Slice
Silicon Dioxide (SiO2) with artificial dye
mineral
Jasper (specifically Bloodstone/Heliotrope or Dark Green Jasper)
Cryptocrystalline Quartz (SiO2) with inclusions
sedimentary
Sedimentary Rock Fragments
Clastic Sedimentary Rock
sedimentary
Banded Agate
Silicon Dioxide (SiO2) - Variety Agate
mineral
Jasper
Silicon dioxide, SiO2
Mineral
Quartzite Pebble
Quartzite (primarily SiO2)
metamorphic
Green Quartz (Prasiolite/Adventurine)
Silicon Dioxide (SiO2) with inclusions
mineral
Orange Calcite (with White Calcite/Quartz matrix)
Calcium Carbonate (CaCO3)
mineral