Diamond Cut

Diamonds Cut

The cut of the shape is most commonly referred to as
the ‘shape’ of the diamond itself. However, ‘cut’ refers
to the diamond’s proportions and finish.

The choice of diamond cut is often decided by the
original shape of the rough stone, location of internal
flaws or inclusions, the preservation of weight and
popularity of certain shapes amongst consumers. The
cutter’s primary goals are to produce the largest size
diamond and achieve the greatest optical beauty.

Around 1900, the development of diamond saws and
good jewelry lathes enabled the development of
modern diamond cuts, chief among them the round
brilliant cut. It is usually the best choice in terms of
salability and desired optics.

The modern round brilliant consists of 58 facets, (or
57 if the cutlet is excluded); 33 on the crown (the top
half above the middle or girdle of the stone) and 25
on the pavilion (the lower half below the girdle). Many
girdles have 32, 64, 80, 96 facets; these facets are
not counted in the total. The facet count is usually
standard and they are cut according to mathematical
formulas. Using symmetry, the cutter aligns these
facets at precise angles in relation to each other to
maximize the reflections and refraction of light. Since
the “brilliance” and “fire” of a diamond depends very
much on the angle of the facets in relation to each
other. When a diamond is cut to proper proportions
and is finished well, it should reflect most light out
from the tabletop and make the diamond appear
white when viewed from the top. An inferior cut will
produce a stone that appears dark at the center in
some extreme cases the ring settings may show
through the top of the diamond as shadows. Proper
cutting is the key to a diamond’s beauty and value.

Sometimes the cutters compromise and accept lesser
proportions and symmetry in order to avoid inclusions
or to preserve the carat rating. Since the per-carat
price of diamond is much higher when the stone is
over one carat, many one-carat diamonds are the
result of compromising “Cut” for “Carat”. Some
jewelry experts advise consumers to buy a 0.99 carat
diamond for its better price or buy a 1.10 carat
diamond for its better cut. A 1.00 carat diamond is
usually poorly cut stone.

With the New GIA Grading system providing a single,
comprehensive cut grade for all standard round
brilliant diamonds falling in the GIA D-Z color scale
and Flawless-I3 clarity scale, consumers can now
select a good diamond cut without the need of a
trained eye to see the quality of good “cut”.
Diamonds will receive one of five cut grades from
Excellent to Poor. The New GIA Report will also
contain all the proportions data used to determine
the GIA Cut Grade.