These are exceptional stones, rarely offered to the open market. These will prove to be a great investment for the future, as a buy and hold strategy. Deposits of Australian opal are getting harder to find, increased costs of mining and an emerging global appetite, has seen increased demand put pressure on pricing in recent years. Most of these gems have resided wit the people that have mined them and some mined 20, 30 or 40 years ago. These are tightly held and often go to collections privately. Replacement costs will soar as time goes on, what a great opportunity!