|Fossilized dinosaur bone (aka petrified dino bone) is between 230 - 180 million years old. It was formed when silicate solutions slowly replaced the bone material buried in the sand. The coloration is caused by the associated dissolved elements in the silica solution and is not from the original bone material.
The stones all cut by the author. The first and second stone are doublets with clear agate backing. The third stone is framed with black agate.