Polarised light micrograph of crystals of D- mannitol, an alcohol derived from the sugar mannose. This sugar is found in the 'manna' exuded by the flowering ash, Fraxinus ornus. It is also found in the seaweed Phaeophyta, a brown alga which flourishes in cold ocean water, and it is from this source that mannitol is prepared for commercial use. It is used as a food additive (E421) in confectionery as a sweetener, emulsifier, anti-caking agent, and thickener. It is used in pharmacy for similar purposes. Industrially, it is used in the production of plasticizers and resins. Magnification x10 at 35mm