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 and in ((different angles wear the colors are ""more vibrant))in a dark room and in ((wet conditions)) measurement (30x28x14mm). ((All minerals are sold as is no refund return policy ""please be aware this policy is strictly in force please study the pictures very carefully and read the description before you buy any thing from this store by any change if you don't like the item you are stuck with IT no matter what the case is)) ((not responsible for any mishandling by the shipping company )). (Does ho doesn't have any knowledge of Opal do your research before you buy any Opal specialty untreated opals) ((all Opal bought from this store will be package in a baggy with a bit of water to keep the Opal moisture specially the untreated opals))