This 62ct Massive Crystal Opal Carving is as good as Opal gets!.  The fire is a 5 out of 5 in brightness, and has all colors found in opal.  The back of the stone is polished as well and has a very very pretty red and blue flash fire.  The Fire in this stone is absolutely incredible.  The stone measures a large 60.9 x 30.4 x 9.7mm.  It is set in 14k Yellow gold with Diamond accents.  It comes with an 18 inch Spiga double-link 14k gold chain. 
You can view a quick video here: https://www.youtube.com/watch?v=4AZYzIDyRSQ