COLOR AND FLAWS 137
new Premier mine of South Africa produces many of this character, they are now becoming known
as "Premiers." Generally they are more or less cloudy or milky, with a
bluish tint which changes in some lights to a yellowish or brownish
shade. They are very deceptive, and are often sold under favorable
conditions for better than they are. Many dealers as well as the public
are deceived by them.
These
are the classifications which have grown out of the close methods of
the London Diamond Syndicate, but notwithstanding the sharp lines of
difference which have been drawn, in the determination to extract the
last penny from the public for every item of quality, there yet remain
differences of tint, and quality of color, in individual stones,
sufficient to puzzle the judgment even of the dealer, and it is often
found difficult to match perfectly a pair of stones from a parcel,
closely graded as they are. There is reason too for the fact that
experts sometimes differ in their judgment when comparing two
particular stones.
To
understand the condition, it should be remembered that color is not a
thing of itself or an exact quantity or quality of a thing, but an
optical phenomenon. It is a sensation conveyed through the eye to the
brain by vibrations or waves of certain lengths and rapidities of
motion, which in the transmission become to us what we know as color,
some waves producing the sensation of one color, some another, as sound
varies to the ear in the notes of an octave. The white light of the sun
is Ibe sum of these variations. This white light may be decomposed, and
the constituent rays shown in the spectroscope, as the primary colors
from red to violet, to-
