Gemology Certification Gemstone Cutting & Lapidary Arts

Question 1

What cutting style features a flat top (table) and a series of facets angling down to a pointed base called the culet?

Accepted Answer

Brilliant cut

Answer

The brilliant cut features a large flat table facet on top and angled facets converging toward the culet at the bottom to maximize light return.

Question 2

Which lapidary term describes the ratio of a gemstone's depth to its girdle diameter, critical for light performance?

Accepted Answer

Depth percentage

Answer

Depth percentage is calculated by dividing the stone's total depth by its girdle diameter and multiplying by 100, directly affecting brilliance and light leakage.

Question 3

A 'windowed' gemstone is one in which light passes straight through rather than reflecting back to the eye — what cutting fault causes this?

Accepted Answer

Pavilion angles too shallow

Answer

When pavilion angles are too shallow, light exits through the bottom instead of being internally reflected back through the crown, creating a 'window' effect.

Question 4

What is the name of the thin band that forms the outer edge of a faceted gemstone, separating the crown from the pavilion?

Accepted Answer

Girdle

Answer

The girdle is the narrow band around the widest part of the gemstone that separates the upper crown from the lower pavilion.

Question 5

In faceting, what does the term 'crown angle' refer to?

Accepted Answer

Angle of the upper facets relative to the girdle plane

Answer

The crown angle is measured between the bezel (main crown) facets and the horizontal plane of the girdle, typically around 34–35° in a well-cut round brilliant.

Gemology Certification Practice Test

Gemology Certification Practice Test

Gemology Certification Gemstone Cutting & Lapidary Arts