You can watch a video of myself, cutting this exact stone below.The stone was cut from a piece of solid rough opal, from the Lightning Ridge mines in Australia. The rough was about 20 years old, possibly older when I acquired it. I know this as it came from an older estate sale. I cut the stone in early November, 2020. It is very stable material, Not a single crack or fainted bit of crazingVery minor potch on the backFeatures:21.89 caratsSolid, No treatments, guaranteedN4-N5 DarkBrightness of color play is a 4-5Stone does not display play of color when viewed dead-on.Two distinct patterns are seen: Broad flash, and Chinese writing.22.4mm x 16.99mm x 9.16mmPerfect for a pendant or necklace