Riddle (moon)

What are you?
Are you a mirror for the sun
Shining since the world began?
Are you a pearl, rolling free
From some celestial jewellery?
Are you a censer steeped in balm
Swinging on a seraph's arm?
Are you a chalice full of beams
Or just a fragment of our dreams
Or half of an angel's cymbaline
For flashing their sweet melodies?
Are you Cupid's new-strung bow
Shooting mortal men below
Or are you an eyeball of a god
Glaring down upon earth's sod
Or a lantern hung on heaven's walls
A sorceress’s crystal ball
The worn-out end of a nub of chalk
For drawing on this great black-board?
Are you a flashing lighthouse top
Lest comets wreck upon our rock
Or a bubble billions years old
A silver coin to sun's gold
A smile, blithe, full of grace
A bright young thing's soft-beaming face
A velvet button, bright and new
Sewn on robes of midnight blue
Or just a little silk balloon
Floating by in her dark lagoon?
Quarter, crescent, half or whole
Presider over lovers' souls
Of these things, art thou one
Art thou all, or art thou none?
Pray I would not care as long
As you who shine till kingdom come
Remember me when I am gone.