Answer:
My first is high, My second damp, My whole a tie, A writer's cramp
Being able to interpret the letters on this screen proves that you have this quality.
Glittering points that downward thrust. Sparkling spears that never rust.
A dragon's tooth in a mortal's hand, I kill, I maim, I divide the land.
Though I have neither legs nor feet, my use is for to go; Although I cannot speak, I tell what others want to know
I’m grown from darkness but shine with a pale light. Very round I am and always a lady's delight.