Answer:
I'm written with two letters, said with one and seen with two. What am I?
I am long and slim works in light. Has but one eye and an awful bite.
I can be entertaining until you realize some pieces have been lost.
Glittering points that downward thrust. Sparkling spears that never rust.
I am a sharp looking horse with a flaxen tail. The longer I run the shorter my tail becomes.
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.