4x6 mm Dendritic Opal Table Cut Corner Drilled Cube - 15-16 Inch Moss Cuprite is a copper oxide

Cuprite is a copper oxide mineral frequently found in association with copper deposits as well as azurite

and this phenomenon is thought to be due to impurities of yttrium or organic matter within the crystal lattice

and most commonly found with black inclusions

Smoky Quartz is a translucent smoky brown or gray variety of Quartz

4x6 mm Dendritic Opal Table Cut Corner Drilled Cube - 15-16 Inch Moss Cuprite is a copper oxideThis variety of opal is named "dendritic" for the small inclusions within it that resemble moss or ferns. These inclusions consist of iron, manganese and other metallic oxides captured during the forming of the rock. Opals are hydrated amorphous forms of silica, created when silica hardens within the fissures of other stones.