Yowah Nut conglomeration, polished slab This is a slabbed section of a conglomeration of Australian Yowah nuts. The material dates to the Cretaceous period is and is believed to be about 100 million years old. There is active debate as to whether the original bodies were some kind of natural concretion which shriveled and created empty spaces for precious opal to infill. Another theory is that these are fruiting bodies and tuberous roots from ancient plants. I have dissected hundreds of these bodies and based on my experience as a gardener and a cook, I believe these are ancient vegetables. We do not see the random variability of Thunder Eggs, these structures precisely repeat showing consistent layers and fibrous husks. While the nuts are solid and easy to work, the ironstone that cements them together has variable porosity, is subject to pitting and shows microfractures approaching the purple rind on the edge of the stone. To create a stable, consistently shiny surface that will stay as it is for many years to come, we paint the surface of the raw slab with a low viscosity resin polymer before grinding flat and polishing. The resin is ground away from the fossilized "nuts" and only remains in lower, softer areas of sandy ironstone, preventing passive decay.