This material is hydrophane Opal (crystal type Opal) it's Opal gamble.it may our may not be gem grade material,sow we rather call it display specimen. If you cut it and it works it's is your win. It's easy to crack when the weather is very dry, ((keep it wet always)) (this rough Opal has some inner inclusion and some cracks) ((The photos are taking closeup in a dark room and in ((wet conditions)) ((like all Opals the colors are more vibrant in the dark)). measurement (24.27x22.55x17.52mm). ((All minerals are sold as is no refund return policy))