Is there really a difference between 色素 and 色


What is the difference between 色素{しきそ} and 色{いろ}? Is there a major difference?
According to Jisho they both seem to mean basically the same thing.




I didn't realize until now that there is no straight translation of 色素 in
English, although they are very different in concept.  
( _Pigment_ seems to cover it according to @Nanigashi, but also seems to
usually stand for a certain type of painting material we call 顔料.)

**色** is a _stimulation_ a ray of certain frequency gives to eye.

**色素** is a _material_ that takes on a certain 色. It is found in dyes, paints,
flower petals, or your skin (melanin). WP has an article [Biological
pigment](https://en.wikipedia.org/wiki/Biological_pigment), which defines them
"substances produced by living organisms that have a color resulting from
selective color absorption". Remove the "produced by living organisms" part
and that is the definition of 色素.

