So many people love fossils, and I'm one of them, it's simply mindblowing to discover prehistoric pieces of wood that have converted entirely to hard silica.  We have a garden full of chunks of fossilised wood that are just crying out to be cut and slabbed. 

One of my very favourite cabochons is this piece of Tasmanian fossilised tree fern. 

Fossilized Tree Fern

Tasmania has great conditions for creating fossils and some of the most beautiful examples of fossilised wood in Australia come from there. This particular cabochon has gone into my collection, but here's a piece of fossilised palm wood in glorious creams and blacks that is a wearable piece of the prehistoric.

Petrified palm wood pendant in sterling silver

Found here in my shop.