Did it break clean off? because that's rare if you didn't rip it all the way off the stem you may be able to methodically tie it back to the main branch and have it be ok. Other then that ya you could clone it, hopefully it hasn't been sitting for too long if its off the plant. To clone you are going to need a sharp knife or razor, make a long diagonal cut, dip it into rooting hormone place in a rooting plug of some type, and have a humidity dome. Also you are going to want to mist the clone 1-3 times a day and keep a small light over it, fluorescent is best