Education

The Pavilion Main Method (5.14)

Estimating crown angles with the Pavilion Main Method.

The Pavilion Main Method (5.14)

Estimating crown angles with the Pavilion Main Method.

Judging Crown Angles (5.13)

Judging diamond crown angles.

Judging Crown Angles (5.13)

Judging diamond crown angles.

Proportion Analyzers (5.12)

The 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 the...

Proportion Analyzers (5.12)

The 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 the...

Cut Grade (5.42)

The research of the cut grade system by GIA included a ray-tracing program and computer modeling programs. Eventually it came down to human observation.

Cut Grade (5.42)

The research of the cut grade system by GIA included a ray-tracing program and computer modeling programs. Eventually it came down to human observation.

Measuring Crown Angles (5.11)

Calculating crown angles of a diamond.

Measuring Crown Angles (5.11)

Calculating crown angles of a diamond.

Crown Angle (5.10)

At 34 ½˚, the angle of dispersion is excellent but as GIA has formulated there are many other variations that are acceptable for an excellent cut grade. At 30˚ one...

Crown Angle (5.10)

At 34 ½˚, the angle of dispersion is excellent but as GIA has formulated there are many other variations that are acceptable for an excellent cut grade. At 30˚ one...