<click here for link>In the case of natural pearls the pearlescent lustre is generated by light being reflected and refracted through minuscule platelet-shaped crystals made of aragonite (a form of calcium carbonate) in the
pearl nacre. These colour effects vary with the angle of the viewer, resulting in the characteristic pearly lustre.Other substances that have a pearl-like sheen often contain similar platelet-shaped crystals. The effect
cosmetic chemists strived to reproduce in vanishing creams was eventually also shown to be the result of crystals generated during manufacture.See also: Vanishing Creams
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