If I were you, I would not cut the piece! Carnotite is a uranium mineral and all uranium isotopes are alpha emitters. If you were to breath any of the dust it would probably lodge in your lungs where the alpha particles would bombard surrounding cells and their DNA. The result is very possibly lung cancer.
Alpha particles are not dangerous unless they are lodged inside your body. Normally, they travel only small distances in air; and in any case do not penetrate the skin. Your sample is probably OK as a specimen, but as a precaution, wash your hands after handling it.
From Don Peck - February 09, 2008 at 12:35:33