Answer:
I am a precious little thing, dancing and eating all the time. Watch me from a distance, so you can feel my warm and gentle love. But don't come to close or my next meal you could be!
My first is an insect; my second is a border; my whole puts the face in a tuneful disorder.
I fly, yet I have no wings. I cry, yet I have no eyes. Darkness follows me. Lower light I never see.
I can be quick and then I'm deadly, I am a rock, shell and bone medley. If I was made into a man, I'd make people dream, I gather in my millions By ocean, sea and stream.
Different lights do make me strange, thus into different sizes I will change
It's what light turns into in the night