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Tone in a Gem

    Ok, so, Beth in SC, I'm an ignoramous, educate me! What is
"tone" a gem? I don't remember hearing it mentioned before. 

Noel - You are NOT an ignoramus, you are, like the rest of us,
someone who doesn’t know everything there is to know !!! I
always tell my students the only stupid question is the one you
don’t ask :wink: Next, I am NOT a gemologist or an expert, just someone
who has loved rocks and stones all her life, and loves to
continually learn more (and fortunately there is a LOT more for me
to learn - no shortage!).

I learned about tone (and many other things!) from Richard Wise’s
wonderful book, which I highly recommend - definitely worth the
money - Secrets of the Gem Trade. Before I read his book I had
never heard of tone either, which is why I was so surprised when
someone came by who obviously DID know what it meant!

Richard says “Tone - that is, lightness and darkness - is the third
component of color.” It is a percentage of color, with no tone
equaling no color, and 100% tone equaling black. This matters,
because each type of stone has a “perfect” tone range. When the
color is outside of that range, it is less than “perfect”, being
either washed-out looking or so dark it loses beauty. This is my
imperfect explanation, based on my understanding of Richard’s
wonderful book. If you are really interested in learning more about
stones and how to tell the best from the rest, then I really do
recommend his book as a good start. It is very readable (I took it
on vacation with me ), and I have at least a rudimentary
understanding of a lot of concepts I didn’t even know existed before
reading it.

I believe Richard has posted on this list before, and would gladly
defer to his explanation!

Beth in SC who has no connection to Richard other than a very
satisfied reader

Hi, Beth, Well, OK, maybe I’m not a complete ignoramus, but I spelled
"ignoramus" wrong, so that doesn’t look good for me… never could
spell well, for some reason. Anyway, so, if I understand right,
“tone” is, for stones, what “value” is to the rest of the art world.
Thank God they came up with a different term. These things are
complicated enough already.

Thanks for the nice, clear explanation. I definately should get the



Thanks for the ringing endorsement of my book. Its true we are not
related in any way but after that post I would gladly adopt you.

Good explanation!, let me expand on it a bit. We think of color as
composed of three elements, hue, saturation and tone. Hue is color
as we normally use the word, e.g. greenish blue is a hue. Saturation
is about brightness of the hue. Some hues are bright (vivid) others
dull. Usually (in the culprit is either gray or brown. A
grayish color is a cool dull hue, a brownish hue is a warm dull hue.
Pure hues are vivid though some are more vivid than others. Tone is
simply lightness or darkness, like adding black to a bucket of paint.
The more black the darker it gets, eventually add enough black and
hue and saturation are both snuffed out and you have black, the
absence of color.

Gems have optimal hue/saturation/tone because each color has an
optimal hue/saturation/tone. I go into this in detail in my book.
For anyone interested you can read sample chapters at Also, a review by Charles
Lewton Brain can be found on Orchid

All this is important to jewelers because we are “jewelers” and
presumably we have a passion. On the more practical side, the
ability to spot a particularly fine gem in a parcel on offer will
often make the difference between making a good profit on a piece
and just getting your labor and material costs back. The fact is:
“You can earn a living making jewelry, you make money selling


Watch for my new book: Secrets Of The Gem Trade:

Visit R. W. Wise, Goldsmith’s online gallery: