Check out Kramer Handgun Leather's website, it has some info on the exotic skins they use. Off the top of my head, I believe some of the exotics are incredibly durable (sharkskin) while others are nowhere near as tough and should be used for decorative purposes only (snakeskin).
Sept 1, 2001 issue of Shotgun News ( www.shotgunnews.com ) has an article by R.K. Campbell titled Exotic Holsters. Some info on the merits of various skins.
