This is a 3D model of the Yarnbury Castle 28-04-2012 formation. The model could be used as a coaster. Polished alumide seems a good material. I might be able to reduce wallthicknesses in order to save costs significantly.
Model can be downloaded freely. I don't charge a personal fee for modeling work. If you wish additional changes I might be able to help you out. For questions, rewards, remarks, feedback, you can contact me @ firstname.lastname@example.org. If you printed one of my products in one of the materials, please send me some photo's or learnings. Be careful with selecting a material.