Malachite is an all purpose healing stone and can be used over any of the chakras or any part of the body. However, it serves best over the solar plexus to clear static or repressed emotions.
Malachite personifies the deep healing green of nature and represents innate beauty of the earth-herbs, flowers, trees, roots and plants. It manifests a deep devic green which rules the material plane.
This stone is dense and nontransparent, and absorbs energy instead of emitting it. It is therefore good to place Malachite stones over areas that are dis-eased or painful to draw out the negative energy and surface the psychic-emotional reasons for it. Because of the absorbing properties, it is important to cleanse these stones after being used for they can become dull and lifeless and lose their power if they take on too much negative energy.
Source: Crystal Enlightenment by Katrina Raphaell