Coal
When buried deep in Mother Earth, the high pressure transforms black coal into clear diamonds; a diamond in the rough.
I am black as night but filled with light. I can be seen, even through a screen. I hold many secrets, waiting for them to be discovered. What am I?
Black I am and much admired, Men seek me until they tired. When they find me, they break my head, And take from me my resting bed. What am I?
I am a precious stone, as clear as diamond. Seek me out while the sun’s near the horizon. Though you can walk on water with my power, try to keep me, and I’ll vanish in an hour. What am I ?