Magnesite is a white magnesium carbonate mineral. It can be found in crystalline form, but is more often found as masses or nodules, as here - they look like clumps of dried chewing-gum to me! NB Some shops mistakenly sell White Howlite for this stone.
Depsite its rather odd appearance I really love this stone, and it is called upon surprisingly often in our grids and layouts. It is one of the main stones used in our layout for Archangel Raphael, for example, which may show that it is useful for use in any healing situation where you need to attract more full-spectrum Light into the body, to help bring about change and balance. Its colour also connects it with the crown and third eye chakras, as well as the Soma and Alpha centres of the Unified Field. This takes the transformative fire and purity of white Light into the head and helps powerfully clear the mind on mental, physical and emotional levels, whilst also charging, clearing and energising the pineal and pituitary glands and hence the 3rd eye and crown chakras and our spiritual bodies.