Like most things, there is no simple answer. Beauty must be broken down into at least two components.
There is the outward appearance, be it a person, a horse, a forest, a painting, a diamond or anything. Something that is pleasing to the senses, be it a beautiful woman, the scent of fresh cut flowers, the sweet smell after a rain, the touch of a furry animal or the sound of the birds singing their songs in the morning.
The next part is the intangible beauty. Is the beautiful woman concerned with helping others or more concern with her own looks. Do the sweet smelling flowers cause adverse skin reactions. Does the furry animal bite and to do birds destroy your gardens as they eat the seeds.
It is said that beauty is in the eye of the beholder. That may be true. I think beauty lies in the mind of the beholder as its combines, subtracts and calculate all the physical, mental and emotional characteristics of a person, animal or object to determine if it is really beautiful.
A beautiful face, can hide ugly thoughts. Beauty as they say is only skin deep. Real beauty is a combination of all parts. Using this approach, even a blind person can identify beauty, where a sighted person may be distracted.