Color words

I have a long-standing interest in languages and linguistics and in color, so of course I'm curious about how various languages refer to colors. Here is a bit of what I've learned, paired with some more-or-less appropriate artwork!

Primitive languages have only two color words
and they are for black and white,
or - more accurately - dark and light.

If a language has only three words for colors,
they are for black, white, and red.
This is because red is so closely associated
with life and death.

Color terms are added in a fixed order
as a language evolves.
Next to arrive are words for green and yellow,
one or the other, and then the other. 

After yellow and green is blue.

All languages distinguishing six colors have terms
for black, white, red, green, yellow and blue.
I wonder if this is why a basic crayon or paint set contains
 those colors and is missing orange and purple?

As languages develop they next add
a term for brown. 

Brown is followed by orange, pink, purple and gray,
in no particular order.

Finally a term for light blue appears.
Russian makes this distinction with 
sinii (dark blue) and goluboi (light blue).
These are as separate and distinct for Russians
as red and pink are for English speakers.

(No, this isn't my art, but it gets the point across nicely!)

Irish apparently has two words for green. 
Glas denotes the green color of plants and the gray-green of the sea,
while uaithne describes the artificial greens of dyes, paints, and such.
Apparently this distinction is made even if the hues are identical.
It seems it's not so much about the color itself,
but about how it came to be.

And there you have a brief history of words for colors.