As rocks go, sandstone is not very hard and every touch removes a little bit of the rock surface and deposits oils onto the sandstone, which contributes to its erosion. Please don't become part of this destructive process. These articles are important clues for archeologists about the daily lives of the Ancestral Puebloans. Leave them in place and report them to a Park Ranger as soon as possible, so that we can all share the value of your discovery. Imagine if everyone who came to Mesa Verde picked flowers, there may be none left for you to see.
Safety is another consideration.
There are places outside of the parks where collecting ecological samples may be appropriate. In our National Parks, however, all objects are to be left alone for our enjoyment and that of future generations. Quiet, respectful visitation is expected in the park. We want you to have fun and enjoy your visit to Mesa Verde but remember that Mesa Verde is an outdoor museum, not a playground. At Mesa Verde, that means to pay attention to your surroundings, where you are walking and what you are doing so that you can prevent injury to yourself and others and prevent the need for medical care.