Crystals
Grey agate
Banded chalcedony Silicon dioxide, SiO2 Cryptocrystalline quartz aggregate Mohs hardness 6.5–7 Silver, dove, blue-grey, smoke, and charcoal bands Grey Agate: Mist-Banded Chalcedony, Quiet Geometry, and the Science of Subtle Color...
Grey agate
Banded chalcedony Silicon dioxide, SiO2 Cryptocrystalline quartz aggregate Mohs hardness 6.5–7 Silver, dove, blue-grey, smoke, and charcoal bands Grey Agate: Mist-Banded Chalcedony, Quiet Geometry, and the Science of Subtle Color...
Moss agate
Inclusion-bearing chalcedony Silicon dioxide, SiO2 Usually unbanded or weakly banded Mohs approximately 6.5–7 Dendritic, plume, cloud, and landscape patterns Green, brown, black, cream, and rust inclusions Moss Agate: Mineral Gardens...
Moss agate
Inclusion-bearing chalcedony Silicon dioxide, SiO2 Usually unbanded or weakly banded Mohs approximately 6.5–7 Dendritic, plume, cloud, and landscape patterns Green, brown, black, cream, and rust inclusions Moss Agate: Mineral Gardens...
Tree agate
Inclusion-bearing chalcedony Silicon dioxide, SiO2 Milky white to semi-translucent host Mohs approximately 6.5–7 Green dendritic and branch-like inclusions Tree Agate: Milky Chalcedony, Green Dendrites, and the Geometry of Mineral Forests...
Tree agate
Inclusion-bearing chalcedony Silicon dioxide, SiO2 Milky white to semi-translucent host Mohs approximately 6.5–7 Green dendritic and branch-like inclusions Tree Agate: Milky Chalcedony, Green Dendrites, and the Geometry of Mineral Forests...
Dalmatian jasper
Trade name: Dalmatian Jasper Feldspar-rich igneous rock Dark amphibole spots Mohs approximately 6–6.5 Classic source: Chihuahua, Mexico Dalmatian Stone: Feldspar, Dark Amphibole, and a Naturally Speckled Igneous Pattern Dalmatian stone,...
Dalmatian jasper
Trade name: Dalmatian Jasper Feldspar-rich igneous rock Dark amphibole spots Mohs approximately 6–6.5 Classic source: Chihuahua, Mexico Dalmatian Stone: Feldspar, Dark Amphibole, and a Naturally Speckled Igneous Pattern Dalmatian stone,...
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...