Sandstone (Ferruginous)
Arenite (primarily SiO2 with iron oxide staining/cementing)
sedimentary
Category
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Dyed Agate Geode (Pink/Magenta)
Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz
mineral
Shale
Shale (Lutite)
sedimentary
Sandstone
Arenite (SiO2 principal component)
sedimentary
Granite
Felsic Intrusive Igneous Rock
igneous
Possible tektite or iron-rich slag-like natural specimen
Uncertain; possibly natural glass (tektite) or magnetite-rich rock
mineral
Shale with Iron Oxide Staining
Fissile Mudstone (primarily clay minerals and quartz)
sedimentary
Shale
Mudstone (composed primarily of clay minerals like kaolinite, illite, and smectite, with quartz and calcite)
sedimentary
Sandstone with Iron Staining
Arenite with Limonite/Hematite inclusions (SiO2 + Fe2O3/FeO(OH))
sedimentary
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2) with Hematite/Limonite
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Shale
Shale (clay-rich mudstone)
sedimentary
Emerald crystal in host rock
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
gemstone
Granite
Granite (Phaneritic igneous rock)
igneous
Granite
Phaneritic Felsic Igneous Rock
igneous
Granite Pebble
Granite (Plutonic Igneous Rock)
igneous
Amethyst Geode
Quartz (Silicon Dioxide, SiO2)
mineral
Tumbled citrine or iron-stained quartz
Quartz (SiO₂), likely iron-oxide-stained or natural citrine
mineral
Sandstone (likely Ferruginous)
Arenite with Iron Oxide cement
sedimentary
Porphyritic Rhyolite
Porphyritic Rhyolite (Felsic volcanic rock)
igneous
Granite
Granite
Igneous
Dyed Blue Agate Slice
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2) with aluminum impurities
mineral
Fossilized coral (likely honeycomb or branching coral)
Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃
fossil
Tumbled dark gray stone, likely basalt
Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, commonly with olivine
igneous
Sandstone (Weathered)
Arenite (primarily SiO2)
sedimentary
Pumice
Pumice (a highly vesicular volcanic rock)
igneous
Emerald in Matrix
Beryllium Aluminum Silicate (Be3Al2(SiO3)6) with Chromium/Vanadium
gemstone
Iron-stained sandstone or weathered ironstone concretion
Quartz-rich sandstone, locally cemented by iron oxides (hematite/goethite); exact identification requires testing
sedimentary
Basalt (Vesicular/Waterworn)
Basalt (Mafic Extrusive Igneous Rock)
igneous
River Quartz (Milky and Smoky mix)
Silicon Dioxide (SiO2)
mineral
Black Beach Pebble (Basalt/Greywacke Pebble)
Aphanitic Mafic Igneous Rock / Basalt
igneous
Red Quartzite / River Siltstone
Quartzite (SiO2 with iron oxide inclusions)
metamorphic
Turquoise
CuAl6(PO4)4(OH)8·4H2O
mineral
Sandstone with Iron Oxide Coating
Arenite (SiO2 with Fe2O3 impurities)
sedimentary
Citrine Quartz
Citrine (Silicon Dioxide - SiO2)
Mineral
Sandstone
Clastic Sedimentary Rock
sedimentary
Banded Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Green Aventurine
Silicon dioxide (SiO2) with Fuchsite inclusions
metamorphic
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Conglomerate
Conglomeratic Sandstone
sedimentary
Pumice
Pumice (a vesicular volcanic glass)
igneous