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Lime paint is also unequalled by its peculiar ability to reflect light. The calcite crystals which lime paint is entirely made of, have birefringent properties.
Birefringence is responsible for the phenomenon of double refraction. when a ray of light encounters a birefringent material, is split by polarization into two rays taking slightly different paths.
When a sunray enters one of these crystals the ray of light splits and radiates twice the light outward giving the building a warm and ever changing appearance.
Before.