Black opal is one of the most enchanting stones in the ... to register your claim can be extremely expensive. Frederick: Really, if you wanted to rock up here and be serious, it'd probably ...

The Most Expensive Black Diamond in the World It's difficult ... There's one for sale at Gem Rock Auctions which is billing itself as the largest musgravite in the world at 16 carats.

Then they must clear out an underground room large enough to start digging out the rock. The equipment ... making it one of the world's most expensive gemstones. Over 90% of black opals come ...