Magnesite

Wikipedia describes magnesite as a mineral that is magnesium carbonate, colourless, white, pale yellow, pale brown, faintly pink or lilac-rose. Hall gives white, grey, brown or yellow, and says it may look brain-like, chalky and marbled, or be crystalline. Hall associates magnesite with bringing deep peace to meditation and relaxation, with visualisation, with heartfelt love including love for the self, and with a calming effect. For the body, Hall says it contains a high level of magnesium. Cunningham has no entry for magnesite, so Hall is the only magical source here. The safety note records the workplace dust limits that Wikipedia reports.