Beauty according to Plato contains essential, timeless, and what is subject to transformations in time, conventions and ideas, this varied determination having its criterion in the absolute idea of beauty. The clarity of the idea of beauty also illuminates all the specific beauty, the rays of the beauty ideas are part of a beautiful one. Plato identifies beauty with good and truth, the interplay of these three creates harmony.
Only what is harmoniously beautiful is inherently unalterable and pure.
Human construct or natural beauty unit, idea?