For thousands of years crystals and gemstones have been used by native healers. Crystals can be held, placed in your environment or used in crystal healing to promote energetic balance and healing.
You do not need to know the exact properties of each of these semi precious stones in order to buy one. Sometimes it is good to just allow yourself to be drawn to a crystal. If you feel that you want that crystal to be a part of your life, it is likely that on some level it has something to offer you.