The more the cutter deviates from the mathematically correct
proportions,In the modern Brilliant Cut the requirements for maximum
the more the brilliance is affected, and the lower is the quality
of the cut.
However, a very slight departure from precise standards does
any loss of brilliance to be seen even by the specialist. It
is therefore normal
practice not to apply exclusively one value, but to extend this
and downwards within narrow tolerances. Only when a "Brilliant
beyond these limits of tolerance can it no longer be graded "excellent"
only either very good, good, fair or poor.
through the table and for the greatest possible play of color
on the upper
crown facets, are fulfilled by a mathematical blending of the
The inter-play of luster, light refraction, total reflection,
and scintillation. All this is the result of the practical experience
craftsmanship of the cutter, along with his applied understanding
law; for only when precisely calculated planes and angles are
used in the
brilliant cut does the stone attain its' greatest possible beauty.
Luster, produced by the reflection of light on the surface of
Refraction of total reflection of light on the pavilion facets.
Splitting and scattering of light into its spectral colors.
The sparkle of the stone when moved, caused by light reflections
light source. It is the term used for the changing colors, the
sparkle of the rays when the stone is moved or when the light
The ratio of the crown to the pavilion, and the thickness of
the girdle, are
the most important considerations when judging total height.
correct relationship of these proportions is far more important
measuring the total depth alone.
The smaller the table, the more play of color will come through
sloping crown facets.
The quantity of light reflection generated depends on the number,
symmetrical arrangements of the facets, as well as on the quality
Because of the steeply rising prices of rough diamonds, there
has been a
tendency over the last few years to save weight when cutting
practice has led to round brilliants with a very shallow crown
resultant larger table. These shallow brilliants look larger
than a precision cut
stone of equal weight, but the dispersion based on the color
diminished because of the smaller crown facets. In a brilliant
cut with a shallow
crown and large table, the major part of the light reflected
on the pavilion
facets passes through the table without being scattered.