Ralph Waldo Emerson

Emerson had this rare talent to sound poetic even when he was writing in prose. These beautiful words about beauty do sound as a poetry and a music, I love them:

"Never lose an opportunity of seeing anything that is beautiful, for beauty is God's handwriting, a wayside sacrament. Welcome it in every fair face, in every fair sky, in every flower, and thank God for it as a cup of blessing."

Franz Kafka

Kafka was indeed a strange master of saying strange, but somewhat deeply truthful things. One is about beauty:

"Anyone who keeps the ability to see beauty never grows old."

Laurence Sterne

Sterne, with his usual, a bit heavy but elegant eloquence says:

"Beauty has so many charms, one knows not how to speak against it; and when it happens that a graceful figure is the habitation of a virtuous soul, when the beauty of the face speaks out the modesty and humility of the mind, and the justness of the proportion raises our thoughts up to the heart and wisdom of the great Creator, something may be allowed it - and something to the embellishments which set it off; and yet, when the whole apology is read, it will be found at last that beauty, like truth, never is so glorious as when it goes the plainest."

Chrétien de Troyes
This elegant and quite truthful phrase is attibuted to Chrétien de Troyes, a French poet and trouvère, supreme master of the Courtly Love (Amour courtois et "fin'amors") poetry, living in the second half of the 12th century:

"Beauty, without virtue, is like a flower without perfume."

Sri Chinmoy

This is very beautiful (and very sad, sadness is often akin to beauty...) poem, called "The Eye of My Eye":

By whose touch does the lily smile

And open its beauty – bud?

Whose moonlit beauty

Do I see in the lily?

Who is the Eye of my eye;

Who is the Heart of my heart?

Alas, then why do I not see Her,

Her face of transcendental Beauty,

Even in my dreams?

Rabindranath Tagore

I like a lot this, very concise and mystical, definition by Tagore:

"Beauty is truth's smile

when she beholds her own face in

a perfect mirror."

Lord Byron (from 'Don Juan')

Her glossy hair was cluster'd o'er a brow

Bright with intelligence, and fair and smooth;

Her eyebrow's shape was like the aerial bow,

Her cheek all purple with the beam of youth,

Mounting, at times, to a transparent glow,

As if her veins ran lightning.

Visvanatha
The experience of beauty is pure, self-manifested, compounded equally of joy and consciousness, free from admixture of any other perception, the very twin brother of mystical experience, and the very life of it is supersensuous wonder... It is enjoyed by those who are competent thereto, in identity, just as the form of God is itself the joy with which it is recognized.

Ryo-Nen

[What follows is the very last composition of a Zen nun, who had been in her youth a great beauty and a great poetess:]

Sixty-six times have these eyes beheld the changing scenes of Autumn.

I have said enough about moonlight.

Ask me no more.

Only listen to the voice of pines and cedars, when no wind stirs.

Lord Byron (George Gordon Noel Byron)

The nameless charms unmark'd by her alone.

The light of love, the purity of grace,

The mind, the music breathing from her face,

The heart whose softness harmonized the whole,

And, oh! that eye was in itself a soul.