CDG Diamond Cutting & Polishing Standards

Question 1

What is the main goal of diamond cutting?

Accepted Answer

To maximize brilliance and fire

Answer

The main goal of diamond cutting is to maximize the diamond's optical properties, specifically its brilliance (white light reflection), fire (dispersion of light into spectral colors), and scintillation (sparkle). An expertly cut diamond will reflect and refract light efficiently, creating a dazzling display. This process often involves sacrificing carat weight to achieve optimal beauty.

Question 2

What tool is commonly used to cut diamonds?

Accepted Answer

Diamond saws

Answer

Due to diamond's extreme hardness, specialized tools are required for its cutting. Diamond saws, which are thin blades impregnated with diamond dust, are commonly used to precisely cut rough diamonds into smaller sections or to remove inclusions. Lasers are also employed for more intricate cuts, but diamond saws remain fundamental for initial shaping.

Question 3

What does polishing do to a diamond?

Accepted Answer

Removes surface roughness

Answer

Polishing is the final and crucial stage of diamond cutting, where the facets are meticulously smoothed to a high shine. This process removes any microscopic surface roughness or scratches left from the cutting and bruting stages. A perfectly polished surface is essential for maximizing a diamond's ability to reflect and refract light, thereby enhancing its brilliance and sparkle.

Question 4

What is 'symmetry' in diamond cutting?

Accepted Answer

Uniformity of facet arrangement

Answer

Symmetry in diamond cutting refers to the precision and balance of a diamond's facet arrangement and overall shape. It evaluates how well the facets are aligned, proportioned, and meet at precise points, ensuring the diamond is perfectly round and its facets are evenly distributed. Excellent symmetry is critical for optimal light performance, allowing light to reflect and refract uniformly within the stone.

Question 5

Why is the pavilion angle important in cutting?

Accepted Answer

It controls light reflection

Answer

The pavilion angle, which is the angle formed by the pavilion facets and the girdle, is a critical factor in a diamond's cut quality. An optimal pavilion angle ensures that light entering the diamond is internally reflected back through the crown, maximizing its brilliance and fire. If the angle is too shallow or too steep, light will 'leak' out the bottom or sides, diminishing the diamond's sparkle.

(CDG) Certified Diamond Grader Practice Test

(CDG) Certified Diamond Grader Practice Test

CDG Diamond Cutting & Polishing Standards