Crystals
Smoky quartz
Macrocrystalline quartz, SiO2 Brown color from irradiation-activated aluminum defects Mohs 7, specific gravity approximately 2.65 Trigonal, uniaxial positive, no cleavage Cairngorm, morion, phantoms, scepters, and gwindels “Smoky topaz” is an...
Smoky quartz
Macrocrystalline quartz, SiO2 Brown color from irradiation-activated aluminum defects Mohs 7, specific gravity approximately 2.65 Trigonal, uniaxial positive, no cleavage Cairngorm, morion, phantoms, scepters, and gwindels “Smoky topaz” is an...
Snakeskin jasper
Trade-named jaspilite and banded iron formation Red iron-rich bands with pale chert laminae Classic source: Turee Creek, Pilbara, Western Australia Formation age approximately 2.45 billion years Folds, microbands, scale-like cells,...
Snakeskin jasper
Trade-named jaspilite and banded iron formation Red iron-rich bands with pale chert laminae Classic source: Turee Creek, Pilbara, Western Australia Formation age approximately 2.45 billion years Folds, microbands, scale-like cells,...
Apache tear
Rounded nodules of natural obsidian Silica-rich rhyolitic volcanic glass Amorphous rather than crystalline Mohs approximately 5–5.5 Warm brown translucency in strong backlight Conchoidal fracture and exceptionally sharp fresh edges Apache...
Apache tear
Rounded nodules of natural obsidian Silica-rich rhyolitic volcanic glass Amorphous rather than crystalline Mohs approximately 5–5.5 Warm brown translucency in strong backlight Conchoidal fracture and exceptionally sharp fresh edges Apache...
Lapis lazuli
Lazurite-rich metamorphic rock (Na,Ca)8(AlSiO4)6(S,SO4,Cl)2 Sodalite-group framework Bulk hardness commonly about 5–5.5 Brassy pyrite inclusions White calcite veins and clouds Ultramarine from sulfur radical anions Historic source: Badakhshan, Afghanistan Lapis Lazuli:...
Lapis lazuli
Lazurite-rich metamorphic rock (Na,Ca)8(AlSiO4)6(S,SO4,Cl)2 Sodalite-group framework Bulk hardness commonly about 5–5.5 Brassy pyrite inclusions White calcite veins and clouds Ultramarine from sulfur radical anions Historic source: Badakhshan, Afghanistan Lapis Lazuli:...
Crazy lace agate
Chalcedony Banded agate SiO2 Mohs 6.5–7 Classic source: Mexico Crazy Lace Agate: Warm Ribbons, Earth-Drawn Lace, and Steady Joy Crazy Lace Agate is a patterned variety of chalcedony admired for...
Crazy lace agate
Chalcedony Banded agate SiO2 Mohs 6.5–7 Classic source: Mexico Crazy Lace Agate: Warm Ribbons, Earth-Drawn Lace, and Steady Joy Crazy Lace Agate is a patterned variety of chalcedony admired for...
Crinoide fossil
Marine echinoderm Class Crinoidea Ordovician to Recent Calcite skeleton Commonly CaCO3; sometimes silicified Crinoid Fossils: Sea Lilies, Columnal Stars, and the Architecture of Ancient Seas Crinoids are marine animals related...
Crinoide fossil
Marine echinoderm Class Crinoidea Ordovician to Recent Calcite skeleton Commonly CaCO3; sometimes silicified Crinoid Fossils: Sea Lilies, Columnal Stars, and the Architecture of Ancient Seas Crinoids are marine animals related...