if diamonds are just carbon pressed together, why are they clear when stuff like coal is black?

Question

if diamonds are just carbon pressed together, why are they clear when stuff like coal is black?

In: Earth Science

Answer 1

Because diamonds aren’t “just carbon pressed together”. They are carbon atoms in a very specific cystalline formation. At an atomic level the carbon atoms are in a very specific and rigid shape, one whose shape allows the passage of visible light through it.

In contrast, just normal coal has the atoms in a rather random collection, one where light cannot pass through it and instead it gets absorbed.