The black market suggests illegal possession and sales. All natural items are legally acquired and sold according to strict laws, including permits, licensing, and the required tags. I personally don't kill an animal specifically for it's fur. If an animal I have is hunted by me, I make use of the meat and bones as well, wasting none of said animal.
Antique hides are pieces of treasured history that wouldn't exist otherwise and couldn't be viewed had they not been preserved.
No animal is in my possession with the strict intent of monitary gain. Natural items are a valued resource for referencing for art, sculpting, and recreating in manmade materials for costumes, masks, and many other textile arts.