Opal is a unique gem known for its colorful phenomenon called play-of-color. However, not all opals display play-of-color. There are several different types of opals: black opal, white opal, crystal opal, boulder opal, and fire opal.
In 1938, The Aurora Australis opal was dug up from an old sea bed at Lightning Ridge, New South Wales and is considered to be the most valuable Australian black opal. In 2005, it was valued at AUD$1,000,000. Aside from its vibrant blues, greens, and reds, it also has a distinctive impression of an actual starfish on its reverse!
The Fire Queen is a famous opal with an unusual history attached to it. Originally named The Dunstan Stone after its finder, Charlie Dunstan, this opal weighed over 900 carats and was deemed "too beautiful for words". At the time, Dunstan wound up selling the opal for a mere £100. After losing two more stones of value, Dunstan was found dead as a result of suicide, in 1910. In 1928, after changing hands several times, the opal wound up in the Chicago Museum. In the 1940s, J.D. Rockefeller purchased the opal for £75,000, adding it to his personal collection.