Answer:
There are millions of me. I am very small but when moving fast I am deadly.
There are two meanings to me. With one I may need to be broken, with the other I hold on. My favorite characteristic is my charming dimple.
Neither bought nor sold but more valuable than gold. It is built but not by hand. What is it?
A seed am I, three letters make my name. Take away two and I still sound the same.
Whoever makes it, tells it not. Whoever takes it, knows it not. Whoever knows it, wants it not
I’m grown from darkness but shine with a pale light. Very round I am and always a lady's delight.