4x6 mm Dendritic Opal Table Cut Corner Drilled Cube - 15-16 Inch birthstone_turquoise This stone is composed of

This stone is composed of angular fragments of minerals

is a lab-made form of zirconium dioxide

if desired

It won 1st price and has been used ever since in sculpture

although sometimes mistaken for Jasper

4x6 mm Dendritic Opal Table Cut Corner Drilled Cube - 15-16 Inch birthstone_turquoise This stone is composed ofThis 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.