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FIGURE 16. Orientcd ice crystals growing on freshly cleaved covellite (cos).
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crystals showing di‘erent interference colours where they are astride a step on the substrate.
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b. A crystal beginning to thicken after being damaged by scratching.
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Layers spreading outward from the point of contact of two crystals of different thickness.
d. A crystal evaporating by layers.
FIGURE 14. Effect of a trace of camphor on ice crystal habit.
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FIGURE 19. Hexagonal etch pits produced by slow evaporation through a formvar lm.