This is a spectacular plate of Early Cretaceous opalized fossils
from the Coober Pedy opal fields of South Australia. This 8.3x7" plate is covered with fossil clams replaced with precious opal of the genus Cyrenopsis. There are also several gastropods present as well as a super rare partial opalized crinoid. These opalized fossils are getting extremely difficult to come buy because the opal fields have barely been worked in years for economic reasons.
While the matrix has been removed from around the fossils on the plate, none of them have been polished or otherwise coated in lacquer to which would enhance the color. Even so you can still see some colorful play of green and purples in the opal.
Truly a spectacular specimen.