Black opal is one of the rarest gemstones in the ... And the price of larger stones has risen by as much as 25 times. In 2000, jewelry company Le Vian capitalized on the underappreciated naturally ...

4–5). This deposit still produces large amounts of white and crystal precious opal and occasionally some black material (Winter 2011 Lab Notes, pp. 312–313). In 2013, yet another source was discovered ...