It has long been known that natural fluorite, exposed to X-ray, γ-ray, or electron radiation develops diffuse purple-pink color banding. However, irradiation from 2.5 MeV protons or α-particles with doses of from 5 to 50 μC/mm2 develops color banding in extraordinary detail. This color banding is crossed by colored lines which are shown to be decorated growth dislocations. Deformation-induced dislocations decorated in the same manner are difficult to resolve by optical microscopy; nevertheless the effects of both brittle and plastic deformation are revealed by proton irradiation. Healed fracture surfaces, subgrain boundaries, kink- and deformation-band boundaries are all colored by the irradiation treatment. Although proton irradiation of fluorite provides the same type of information as that obtainable by X-ray topography, the technique is direct, rapid, has high resolution, and is applicable to samples with any degree of deformation.

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