NATURAL BOULDER OPAL AUSTRALIA UNTREATED
Weight: 15.69 carat
Gem Type:  Natural Opal.
Shape: Free Form Cabochon.
Size in millimeter: 21.6 Length. 14.0
Width. 6.5 Deep Color: Blue Lightning.
Luster: Iridescent. Origin: Australia.
Treatment: Unheated, Untreated.
Hardness: 5.0 to 6.5.