of course you can! can you be more specific with your question? are you asking if it's appropriate to use "plain" stones for healing? my answer is still yes. if a stone or found object speaks to you, i think that is the first step in creating a dynamic of intention between you and that object.
i would add that we should not take too many objects from nature. "collecting" tends to be a human activity that can get out of control if it's not approached mindfully. most of the time when i am in nature i will make an effort to put things back as i found them whenever possible. but that said, if some particular small item feels very "important" to you, it is appropriate to sit down with it where you found it, and "ask" the stone or leaf or branch or whatever, if it is okay to take it away with you. if you do this in an open-minded and respectful manner, you will find that almost always you can hear an answer. (and if the answer is "no"—which sometimes does happen—please respect it, and gently replace the object where you found it.
one more note: in many state and national parks (in the U.S., at any rate) it is technically illegal to pick flowers, gather, or in any way remove natural items from the area. not that people don't do it all the time anyway, but really... it's better to leave things as untouched as possible. keep it beautiful and unspoiled for everyone who comes after to enjoy.
i hope this answer helps, moonseekerjade. and welcome to hubpages! i look forward to reading your first hub.