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Gem
Criteria
Clarity, or freedom from flaws, largely determines value
in the case of faceted gems. In past times flawed stones
were considered attractive, but today's fashion associates
high value with complete absence of inclusions or flaws.
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Since
most minerals acquire such internal imperfec¬tions
as a normal part of the growth process, completely flawless
or "clean" gems are extremely scarce in many
species. In Colombian emerald and Burmese ruby, for
example, such perfection is almost unknown. |
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Even
nearly flawless gems of such materials are in great demand
and command a high price. In the case of quartz and topaz,
on the other hand, large transparent and clean gems are frequently
cut. Transparency is the absence of "cloudiness"
or "milkiness" that would scatter light entering
a gem.
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DIAMONDS,
GEMSTONES & CRYSTALS
FACTS & FIGURES |
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faceted gemstone may be free of inclu¬sions
or flaws visible to the naked eye, but might contain
thousands of tiny bubbles or mineral inclusions
that could be resolved only under high magnification.
Examples are the bubbles in white quartz and the
"silk" in star sapphires.
Beauty
is the most important criterion of all. It depends,
of course, on the judgment of the observer and
is thus almost totally subjective. But more significant
is the fact that what is generally considered
beautiful or desirable may change with time, and
vary from one culture to another. The value of
gems is thus intimately linked to fashion, and
the vogue of the time.
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Portability
is a less obvious but very important aspect of
gem value. You can close your fist around a diamond
worth several million dollars. Only a gem can
offer this degree of high value captured in a
small space. Many a fortune has been saved because
its owner could escape economic or political upheaval
carrying his gem hoard easily con¬cealed on
his or her person. |
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Few
gems display in perfection all of the above criteria, and
even the criteria themselves have modifying factors. For instance,
a dark color might be desirable in a green tourmaline, but
if the color is too dark the gem actually may lose value.
A large gem might be far more valuable than a smaller one,
but the larger stone might be less saleable because of its
higher cost. A gem may possess great value because of its
scarcity. But if the gem is so scarce that few people have
ever heard of it, its 14 marketability, and hence its value,
may be less than expected. |
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