Answer:
You can read me both ways I wear; One way it's a number reversed a snare.
I have six faces but not even one body connected 21 eyes in total but cannot see.
While you were folding a letter you got me. Usually you will do whatever it takes to avoid me but now you can't help but find me.
I am an instrument capable of making numerous sound but cannot be touched or seen.
My first is second in line; I send shivers up your spine; not quite shining bright I glitter in the light.
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.