This free-form cabochon of Dinosaur bone was made by Steve Leidenthal. Notice the rough edge at the top that highlights the natural nature of the specimen.  Petrified dino bone like this clearly shows the separations in the soft marrow. I love the bright colors on this one.

 Steve also made this free-form Whale bone cabochon. It also highlights the original coarse edge of the bone specimen.


Depending on where the bone was fossilized, it may have been exposed to minerals that can add considerable color--or not. Some remains a dull brown no matter how much you polish it. However, on a better specimen you will find red when either Iron or Hematite are found in the petrified bone  you are working on.  

Dan and Denise Schaefer  own the web site and they allowed me to use several of their dinosaur gembone images including this one. What incredible color they have! 

You may also be surprised to discover jaspers, agates, and other minerals have replaced the original softish tissue in the bone. If you're lucky, you may find that the center of the petrified bone has filled with quartz or other crystals


Courtesy of UCMP Collections   
This topic of this post is cabbing petrified bones but I recently saw an image at a program on fossils given by  Cristina M. Robins, PhD, Senior Museum Scientist at the University of California Museum of Paleontology that I couldn't resist sharing with you.  This image shows a fossilized whale skull and instead of the crystals growing in the bone, they grew inside the skull where the brain had been. Isn't it amazing?