What Can a Gemologist Learn from Diamond Type?
In many cases, the geologic conditions to which natural
diamonds have been exposed during their
extended period in the earth and the conditions
imposed in a laboratory during treatment or synthetic
growth are quite different, yet the resulting structural
lattice defects can yield natural, treated, and
synthetic diamonds with very similar colors. (See box
A for information about non–type related defects that
also influence color.) Diamond impurities control the
nature of the lattice defects that occur naturally and
their evolution during lab growth or treatment.
Therefore, a diamond’s type reflects its history,
whether in nature or in the laboratory, or both—and
an adequate understanding of diamond type is critical
for identification purposes. Since the detection of
many modern treatments and synthetics requires the
facilities of a well-equipped gemological laboratory, it
is important to know when to send a diamond for
advanced testing. With a better understanding of how
diamond type relates to natural color, treated color,
and synthetic growth processes, a gemologist should
be able to make that decision more easily.