National Parks & Rockhounds
Question: May I collect specimens inside National Parks?
Answer: No. Rockhounding inside National Parks (e.g., Yellowstone National Park, Petrified Forest National Park) is prohibited. This seems so basic that it doesn't need to be said. But, sadly, people are people. In Yellowstone National Park, for example, individuals have walked away with enormous amounts of obsidian from the famed obsidian cliff. Similarly, individuals - one piece at a time - have stolen an entire large fossilized stump from Yellowstone Park. It's gone. One of the remaining fossilized stumps now is fenced to decrease theft and damage (which, for the law abiding folks, makes for a tacky photo).
Sign at Obsidian Cliff in Yellowstone National Park
Petrified Stump with Fence to Decrease Theft inside Yellowstone National Park