Anatomy of a diamond

Crown

Just like you would wear a crown on your head, a diamond crown is the topmost part of the stone. It contains everything that sits above the diamond belt.

When light passes through the crown, it is reflected from the pavilion (base) back to the viewer’s eyes. All diamond facets reflect light in different directions for a multi-faceted light show.

CROWN HEIGHT: The height of the crown affects the brightness and fire of a diamond (the amount of colored light that is reflected from the stone).

CROWN ANGLE:The angle from the top of the belt to the diamond table (flat top). This angle affects the brilliance and fire of a diamond from above. A well-cut diamond has a crown angle between 31.5 and 36.5 degrees (these measurements can be found in all GIA evaluation reports).

belt

The widest edge of the diamond where the crown and pavilion (base) meet. A well-cut diamond has a goldilocks belt – not too thin and not too thick. A belt that is too thin can risk chipping, while a belt that is too thick puts too much weight in the center of the diamond and makes it appear smaller than diamonds of comparable carat weight.

If the belt thickness is incorrect, a diamond can only get a maximum very good GIA cut rating regardless of all other factors.

pavilion

The lower part of the diamond that starts at the belt and ends at the schnitzel (pointed base). Most of the diamond weight is in the pavilion.

PAVILION DEPTH:Another measurement of goldilocks, a pavilion that is too “deep” or too “shallow”, allows light to leak through the sides or bottom of the stone, creating a dull, lifeless looking diamond. A well cut diamond allows light to reflect through the top of the stone, creating a brilliant, glowing shine.

PAVILION ANGLE:Ok, get ready for the geometry lesson – this is “the average of the angles made by the main facets of the diamond pavilion and its belt plane”. What you need to know: a diamond with an excellent cut has a pavilion angle between 40.6 and 41.8 degrees and sparkles with radiant brightness.

table

The flat, top (and largest) facet of the diamond – what you see from a bird’s eye view. The diamond table breaks (bends) incident light rays, which are then reflected from the pavilion back into the viewer’s eyes.

TABLE SIZE:The table size is measured in relation to the belt diameter. An excellent quality diamond has a table size of 52 to 62 percent, along with all of the other appropriate dimensions and proportions that make up a well-cut diamond.

depth

The total height of a diamond from the table to the shavings – this is measured as a percentage of the belt diameter. Diamonds from very good to ideal have a depth of 54 to 66 percent.

chop

The small pointed facet at the base of the diamond. It is as big as none, very small, small, medium, slightly large, large, very large or extremely large.

Excellent cut diamonds fall into the “none to small” category, which means that the chip is invisible to the naked eye. Larger chips are less desirable as they allow light to escape through the bottom of the diamond.

This motto “smaller is better” applies mainly to modern cut diamonds. Old cut diamonds had much larger chips that will draw your eye into the stone and have their own unique beauty!

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