Crystals
Brecciated jasper
Jasper and chalcedony Angular breccia texture Silica-rich, commonly SiO2 Mohs approximately 6.5–7 Iron-oxide reds Brecciated Jasper: Fracture, Silica Cement, and a Stone Reassembled Brecciated jasper is a naturally fragmented and...
Brecciated jasper
Jasper and chalcedony Angular breccia texture Silica-rich, commonly SiO2 Mohs approximately 6.5–7 Iron-oxide reds Brecciated Jasper: Fracture, Silica Cement, and a Stone Reassembled Brecciated jasper is a naturally fragmented and...
Coral
Biogenic and organic gem materials CaCO3 skeletons in many groups Protein-rich axis in black coral Recent coral: Mohs approximately 3–4 Aragonitic blue coral Colonial skeletal architecture Dye and resin treatment...
Coral
Biogenic and organic gem materials CaCO3 skeletons in many groups Protein-rich axis in black coral Recent coral: Mohs approximately 3–4 Aragonitic blue coral Colonial skeletal architecture Dye and resin treatment...
Desert rose
Sulfate mineral rosette Gypsum or barite CaSO4·2H2O BaSO4 Sand-rich bladed crystals Desert Rose: Gypsum and Barite Rosettes Formed by Evaporation, Sand, and Time Desert rose is a descriptive name for...
Desert rose
Sulfate mineral rosette Gypsum or barite CaSO4·2H2O BaSO4 Sand-rich bladed crystals Desert Rose: Gypsum and Barite Rosettes Formed by Evaporation, Sand, and Time Desert rose is a descriptive name for...
Iceland spar
Transparent optical calcite Calcium carbonate, CaCO3 Trigonal crystal system Mohs hardness 3 Exceptionally strong birefringence Perfect rhombohedral cleavage Iceland Spar: Clear Calcite, Double Refraction, and the Geometry of Polarized Light...
Iceland spar
Transparent optical calcite Calcium carbonate, CaCO3 Trigonal crystal system Mohs hardness 3 Exceptionally strong birefringence Perfect rhombohedral cleavage Iceland Spar: Clear Calcite, Double Refraction, and the Geometry of Polarized Light...
Kambaba jasper
Trade-named orbicular volcanic rock Quartz and alkali feldspar groundmass Radial amphibole-rich aggregates Fine aegirine overgrowths and rims Composite hardness approximately 5–7 Commercially associated with Madagascar Kambaba Stone: Orbicular Volcanic Rock,...
Kambaba jasper
Trade-named orbicular volcanic rock Quartz and alkali feldspar groundmass Radial amphibole-rich aggregates Fine aegirine overgrowths and rims Composite hardness approximately 5–7 Commercially associated with Madagascar Kambaba Stone: Orbicular Volcanic Rock,...
Leopardite jasper
Trade-named spotted volcanic rock Commonly spherulitic or orbicular rhyolite Quartz and alkali-feldspar groundmass Dark oxide-rich rings and margins Composite hardness approximately 6–7 Opaque, polishable, and pattern-dependent Leopardite: Ringed Spherulites, Spotted...
Leopardite jasper
Trade-named spotted volcanic rock Commonly spherulitic or orbicular rhyolite Quartz and alkali-feldspar groundmass Dark oxide-rich rings and margins Composite hardness approximately 6–7 Opaque, polishable, and pattern-dependent Leopardite: Ringed Spherulites, Spotted...