Opal

A lovely and quite striking example of Boulder Opal, a form of precious Opal coating and filling cracks in a matrix of deep chocolate-brown ironstone.  The only location retained with this specimen is that of Australia, but it most probably originates form Queensland, where Boulder Opal is known to occur.  The specimen is very richly coated with Opal on both sides and displays beautiful shades of pale to deep sky-blue, light emerald-greens, orange-buff-yellow, with occasional flashes of electric sapphire-blue.