I was just wondering about colored stones. Perhaps this topic has
come up before.
There seems to be some colored stones out there where color is
paramount. Obviously this important with diamonds and such. I know
the good labs are equipped with spectrophotometers and colorimeters.
L represent lightness level (0-100 units), a is red-green (+/- 50
units), and b is yellow/blue (+/- 50 units). Why don’t they specify
L,a,b color values for stones instead of guessing? Some stones of
value are totally opaque, like black opal. Why don’t they specify
L,a,b of say 25.00, -3.4, 2.4 to quality as a black, and then have
delta E units like +/- 5 units,10 units, and 10 units to be in
specification? You could have similar specifications for other
materials like chrysoprase or lapis lazuli.
You could even use spectrophotometers to check clarity and
transparency through light transmission. You could check to see if
the color of your chrysoprase ring has faded in sunlight, and by how
I mean we all spend up into the $thousands or more for these items.
Why not remove alot of the guesswork?