Blue Chalcedony
Chalcedony (a cryptocrystalline variety of Quartz - SiO₂)
Mineral
Category
Man Made Object (Simulant)
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Red Tigers Eye (Bull's Eye)
SiO2
Mineral
Banded Calcite (often sold as 'Onyx')
Calcite (Calcium Carbonate, CaCO3)
sedimentary
Crazy Lace Agate
Chalcedony (SiO2)
mineral
Nephrite Jade
Ca2(Mg, Fe)5Si8O22(OH)2
metamorphic
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Goldstone and Aura Quartz
Cuprous Glass (Goldstone) and Titanium-coated SiO2 (Aura Quartz)
Mineral/Glass Specimen
Granite
Phaneritic Igneous Rock (composed mostly of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Granite
Phaneritic plutonic rock (SiO2 typically >69%)
igneous
Calcite
Calcium Carbonate (CaCO3)
mineral
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Obsidian (Black Obsidian)
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
igneous
Weathered quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly microcrystalline quartz (SiO₂), with possible feldspar, mica, and iron-oxide staining
metamorphic
Chert (Chocolate or Brown Flint)
Chert (SiO2)
sedimentary
Tumbled jasper or jasper-rich chert
Microcrystalline quartz (SiO₂) with iron-oxide impurities
mineral
Banded agate (likely brown/gray chalcedony)
Microcrystalline quartz, SiO₂ (chalcedony/agate)
mineral
Polished banded jasper pebble
Jasper, a microcrystalline quartz variety (SiO₂), with iron-oxide and clay/mineral impurities
mineral
Polished orbicular jasper
Orbicular jasper; microcrystalline quartz (SiO₂) with hematite/goethite and other silicate inclusions
sedimentary
Dalmatian jasper
Dalmatian stone, typically a leucocratic alkali-feldspar-rich porphyritic igneous rock with black arfvedsonite or aegirine inclusions
igneous
Obsidian (likely mahogany or black obsidian)
Volcanic glass; chiefly amorphous SiO₂-rich rhyolitic composition
igneous
Polished brecciated jasper
Jasper, opaque microcrystalline quartz (SiO₂), with iron-oxide and other mineral inclusions
gemstone
Tumbled jasper pebble
Jasper, microcrystalline quartz (SiO₂) with iron-oxide impurities
mineral
Tumbled brecciated jasper
Silica-rich microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions
mineral
Polished black stone, likely black obsidian
Obsidian (volcanic glass), primarily silica-rich rhyolitic composition
igneous
Tumbled brown agate
Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions
mineral
Polished serpentine pebble
Serpentinite, chiefly serpentine-group minerals (chrysotile, lizardite, antigorite)
metamorphic
Tumbled milky quartz
Quartz, silicon dioxide (SiO₂)
mineral
Amethyst geode fragment
Quartz, SiO₂; purple color from irradiation-related iron impurities
mineral
Polished carnelian/chalcedony pebble
Microcrystalline quartz (SiO₂), likely iron-stained chalcedony
gemstone
Tumbled jasper, likely red/brown jasper
Microcrystalline quartz (chalcedony), SiO₂, colored chiefly by iron oxides
mineral
Milky quartz crystal
Quartz, silicon dioxide (SiO₂)
mineral
Polished blue-banded agate slice
Agate (microcrystalline quartz, SiO₂; chiefly chalcedony)
mineral
Selentite
Gypsum (CaSO4·2H2O)
mineral
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Agate
Chalcedony (SiO2)
sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
gemstone
Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Lapis Lazuli
(Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2 (Complex silicate rock)
metamorphic
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Brecciated Jasper
Silicon dioxide (SiO2) microcrystalline quartz breccia
sedimentary
Agate
Silicon dioxide (Chalcedony), SiO2
sedimentary