Polarised light micrograph of crystals of naphthalene, a white, crystalline hydrocarbon with a characteristic penetrating odour. It is used as a moth repellant in the form of moth balls or flakes. It is also found in the manufacture of acids & compounds used in the dye industries & in the production of synthetic resins & celluloids. Naphthalene is also the single most abundant constituent of coal tar. Magnification: x60 at 35mm size.