Education

The Pavilion Main Method 5.14

The Pavilion Main Method (5.14)The Pavilion Main Method is another effective way to estimate crown angles without the use of instruments. The elongated kite-shaped “pavilion main” can be viewed through...

Judging Angles 5.13

Judging Angles (5.13)For buying purposes, many dealers rely on their judgment of determining proper specs with only a 10x loupe, cleaning cloth and a pair of tweezers. This takes a...

Proportionscope 5.12

Proportionscope (5.12)A proportionscope, first designed and manufactured by GIA in 1967, is an instrument that casts a silhouetted image of the diamond It allows us to check the proportions of...

Measuring Crown Angles 5.11

Measuring Crown Angles (5.11)Diamond cutters use a star gauge to measure the crown angle from the table, which should -- if the stone is accurately cut -- coincide with the...

Crown Angle 5.10

Crown Angle (5.10)The original ideal angle for the crown is 34.5°. Here again, the major gem labs do agree that slight variations from this angle will still produce a well-cut...

Pavilion Angle 5.09

Pavilion Angle (5.09)The original ideal pavilion angle is 40.75˚. The major gem labs do agree that slight variations from this angle will still produce a well-cut diamond. This chosen angle...