Opal Replacing Bivalve Fossil

One of the great classics in terms of Australian Opal. The myriads of Opal found in Australia ranges from the finest Black Opals in the world to many precious multi-color Opals including what I believe are the most iconic Opal / fossil pseudomorphs extant. This piece was mined in the mid-1960s and features a well-preserved bivalve mollusk shell which has been not only fossilized but partially replaced by gemmy multi-color Precious Opal. The top portion of the piece features flashes of glowing green, blue, purple Opal (with tiny red and orange spots here and there) which glow in the light. Additionally, when the piece is backlit, you can see a bit of a golden interior. I love the fact that you can see the striations / growth lines of the shell, so it's clearly NOT polished and very well-preserved! The piece is complete all around, though there is a small point on the top where it was contacted, exposing the interior Opal. These Opal-replaced fossil shells are RARE and formed 135 million years ago in the Bulldog Shale of Coober Pedy. Unfortunately, these specimens are virtually impossible to find on the market now as the area around Coober Pedy is difficult to mine since it is no longer profitable or commercially successful for the effort required. A beautiful, fine quality and desirable example of these gorgeous pseudomorphs. Ex. Brian Kosnar collection Specimen #WWMIX12101