OVERTONE CHARTS (Continued…)

The following is a chart showing overtones certain gemstones are likely to have.

NAME OF GEMSTONE          OVERTONES          CLASSIFICATION

TOURMALINE
———————————————————————————————————–

[Green]
Pure Green +yellow undesirable
+blue good
+brown bad
+gray bad
Blue-Green +yellow bad in excess
+brown bad
+gray bad
Chrome-Green +yellow bad
+brown bad
+gray bad
+blue good
[Pink]
Pure Pink +yellow bad
+brown bad
+blue good
Brown Pink +gray bad
+yellow bad
+blue good
+gray bad
[Rubellite]
Hot Pink +yellow bad
+blue good
+brown bad
Red +gray bad
+yellow bad
+blue good except in excess
+brown bad
+gray bad
[Bi-Colors]
Pink or Green +yellow bad
+blue good (hot pink)
+brown bad
+gray bad
Red or Green +yellow bad
+blue good
+brown bad
+gray bad
[lndicolite (Blue
Tourmaline)]
Blue +brown bad
+gray bad

ZIRCON
———————————————————————————————————–

[Red to Brown] +yellow bad
+gray bad
+green bad
+red good
[Blue] +brown bad
+gray bad
+yellow bad
+green bad
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OVERTONE CHARTS (Continued…)

The following is a chart showing overtones certain gemstones are likely to have.

NAME OF GEMSTONE          OVERTONES          CLASSIFICATION

SPINEL
———————————————————————————————————–

[Red Spinel] +brown bad
+gray bad
+blue good except in excess
+yellow bad
[Blue Spinel] +gray bad
+purple acceptable in minute
amounts but not
Desirable
[Orange (Flame)] +brown bad
+red acceptable
+gray bad
[Purple & Lavender
Spinel]
+brown bad
+gray bad
+pink good
+blue good
+green bad

SPODUMENE (Kunzite)
———————————————————————————————————–

[Pink or Purple] +yellow bad
+gray bad

TANZANITE
———————————————————————————————————–

[Blue] +brown bad
+gray bad
+purple acceptable but not
Preferable

IMPERIAL TOPAZ
———————————————————————————————————–

[Yellow, Orange & Red] +yellow bad
+brown bad
+gray bad
+pink good
[Pink] +yellow bad
+brown bad
+gray bad
+blue good (hot pink)

OVERTONE CHARTS (Continued…)

The following is a chart showing overtones certain gemstones are likely to have.

NAME OF GEMSTONE          OVERTONES          CLASSIFICATION

RHODOLITE GARNET
———————————————————————————————————–

[Red/Purple and
Red/Pink] +brown bad
+gray bad
+blue good
+orange bad

RUBY
———————————————————————————————————–

[Red] +blue very, very slight is good
and more is bad
+gray bad
+brown bad
+yellow bad
+pink slight can be acceptable
but not desirable; too
much and it is no longer
ruby, but sapphire.

SAPPHIRE
———————————————————————————————————–

[Blue] +purple any deviation from blue
is not desirable
can be acceptable but
not desirable
+brown bad
+green bad
+gray bad
[Yellow-Gold] +brown bad
+green bad
+orange good
[Pink] +blue good but not in excess
+gray bad
+brown bad
+yellow bad

SPESSARTITE GARNET
———————————————————————————————————–

[Orange] +red acceptable but not
Desirable
+yellow bad
+brown bad but stone may be
Acceptable

OVERTONE CHARTS

The following is a chart showing overtones certain gemstones are likely to have.

NAME OF GEMSTONE          OVERTONES          CLASSIFICATION

ALEXANDRITE
———————————————————————————————————–

[Red phase]

+gray

bad

+brown

bad

+blue

acceptable

[Green phase]

+gray

bad

+brown

bad

+blue

acceptable

+yellow

undesirable

ANDALUSITE
———————————————————————————————————–

+red

good

+gray

bad

+pink

good

BERYL
———————————————————————————————————–

[Aquamarine]

+yellow

bad

+brown

bad

+gray

bad

[Emerald]

+blue

good except in excess

(Colombian “look”)

+yellow

good except in excess

(Russian “look”)

+brown

bad

+gray

bad

CHRYSOBERYL
———————————————————————————————————–

[Yellow]

+brown

undesirable

+gray

undesirable

[Pure Green]

+brown

undesirable

+gray

undesirable

[Chartreuse]

+brown

undesirable

+gray

undesirable

DIAMOND
———————————————————————————————————–

[Colorless]

+yellow

bad

+brown

bad

+gray

bad

+blue

good

+pink

good

[Canary]

Any derivation from Yellow is bad

[Pink]

Hot pink is created by a blue overtone but if overly prevalent turns the pink Into lavender.

[Blue]

Any derivation from blue is bad

GROSSULAR GARNET
———————————————————————————————————–

[Tsavorite]

Pure Green

+blue

Good optimum color

+yellow

bad

+brown

bad

+gray

bad

[Orange]

+yellow

bad

+brown

bad

+gray

bad

+red

good if not in excess

PERIDOT
———————————————————————————————————–

[Green]

+brown

bad

+gray

bad

SENSITIZATIZATION: THE LEXICON OF COLOR (Continued…)

MIXING COLORS

        Now that we have our own color lexicon, we can discuss the mixing of colors. By mixing the three primary colors … red, blue, and yellow, we get secondary colors. Red and blue make purple. Red and yellow make orange. Blue and yellow make green.

        Changing the value makes other name colors. Light red becomes pink. Artists make pink by adding white to red. Lavender is purple that has been similarly treated. Color balance can create name colors as well.
For instance, chartreuse is green with a great deal more yellow than blue. Chartreuse is simply a green that has so much more of one color than the other that it has both a distinct look and name.

        However, when we examine stone species and their colors, we quickly exhaust the name colors: red, yellow, blue, green, violet, orange, pink, and chartreuse. For the rest of the other colors we encounter we must make up names. For instance, when we say “Imperial topaz” we mean a stone composed of gold/yellow and orange with a hint of pink. “Aquamarine” stands for the name of both a beryl variety gemstone and the name of its own color. “Aquamarine” illustrates a very good example of how, in order to describe gem colors, it becomes necessary to find a common denominator in nature to point to and say — “That is the color.” “Aquamarine” has a connotation of a blue hue with just a hint of green, with a color value as well. The color value of aquamarine is not too dark. much as the sea is normally not too dark.

        The lesson of aquamarine helps to point out the type of thinking necessary when dealing with color in gems. While the gem market has assessed the general color of aquamarine, it will be your responsibility to examine each stone offered and decide upon its color.

*(From page 13) The GIA or Gemological Institute of America is a non-profit educational and research institution for gems and jewelry. It is currently located in Carlsbad, California. For further explanation see Education chapter page 58.

SENSITIZATIZATION: THE LEXICON OF COLOR (Continued…)

ANALYZING COLOR IN A CHOSEN GEMSTONE

        Armed with our new vocabulary and awareness of color we can begin looking at gemstones offered for sale and evaluate their color. We do this by asking a series of questions.

1. What color is our stone?
At this point you should be looking at the stone to determine the predominant hue of the body color. If the body color has a name you come up with, give it that label.

2. What are the overtones, if any?
After you have named the predominant color, try to determine the overtones and ask yourself if they are heavy overtones or light overtones? Do they modify the predominant hue a great deal or just a little?

3. In terms of color value, is this gem light, medium, or dark?

4. In terms of saturation, is this tone a good strong, pure: red … blue … green … pink?

5. Ask about shade if you are looking at more than one stone of the same kind in terms of lighter or darker — one stone as opposed to the other. Which shade do you prefer? Which shade is prettier? Which shade is considered better by the experts?

6. Can I see any pleochroism in this stone? Does it enhance or detract from the stone? What do experts consider most desirable regarding pleochroism in this species?

Keep in mind that some pleochroic stones show their pleochroism more than others and in certain stones pleochroism can be considered either a plus or a minus, while in others it makes no difference.

        The main objective in understanding color and asking and answering questions about a particular stone is for you to be able to make decisions based on what you observe. The more you consciously sensitize yourself to color, the more confident you will become in making decisions. Also, you will be able to discuss what you see with others, be they friends, relatives, or strangers. Most importantly, this knowledge enables you to hold your own with the vendor of the stone.

SENSITIZATIZATION: THE LEXICON OF COLOR (Continued…)

OVERTONE

For our purposes, the word “overtone” will refer to a color or colors in addition to the main color of a stone. For example, most rubies exhibit colors in addition to red. The additional colors may be purple, pink, orange or brown. There may be one of these colors or several and they may vary as to what percentage they make up of the total observable color. There may be a great deal of purple and very little orange. In such a case the predominant overtone is purple and the secondary overtone is orange. In most gem varieties, very pure colors are usually the optimum. However in other varieties the overtones are considered to be attractive and will not cause a discount and may even bring a premium. Learn to read the overtones of the gems at which you look. It will help you become more sensitive to color and learn to evaluate the worth of stones more easily.

        “Overtone” = the ancillary colors observable in a stone that modify the main color.