Answer:
I am good at concealing what's real and hide what's true. Sometimes I bring out the courage in you!
Though desert men once called me God today men call me mad. For I wag my tail when I am angry. And growl when I am glad.
I must be broken before you can use me.
Until I am measured, I am not known. Yet, how you miss me when I have flown. What Am I?
I am the noblest musical instrument
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.