moazzamkI notice that you've asked this question on several Orion drops and we've answered it there, so you can assume that this answer applies to all of their belts.
All Orion belts are made of vegetable tanned calf leather. You can read more about their products on their site: http://www.orionleathercompany.com/aboutus.asp
IanAndersonIt was answered once on another drop but by the time I tried to join it was too late. I wasn't sure if all their belts were same leather so I had to make sure. Thanks for answering.