Gemology Certification Gemology Gemstone Grading & Evaluation 3

Question 1

What does a GIA clarity grade of 'SI2' indicate about a diamond?

Accepted Answer

Inclusions are noticeable under 10x magnification but eye-clean

Answer

SI2 (Slightly Included 2) diamonds have inclusions that are easily seen under 10x magnification and may be detectable to a careful naked eye.

Question 2

Blue sapphires from Kashmir are prized for which distinctive optical quality?

Accepted Answer

Velvety, cornflower-blue hue caused by fine rutile silk

Answer

Kashmir sapphires are renowned for a soft, velvety blue appearance resulting from fine rutile silk needles that scatter light within the stone.

Question 3

When evaluating a colored gemstone's color, which factor carries the greatest weight in determining value?

Accepted Answer

Saturation

Answer

Saturation—the intensity or purity of color—generally has the greatest impact on a colored gemstone's value because vivid, highly saturated stones command premium prices.

Question 4

Which gemstone characteristic is described by the term 'adularescence'?

Accepted Answer

A billowy, floating light effect seen in moonstone

Answer

Adularescence is the soft, glowing light phenomenon seen in moonstone, caused by light scattering between alternating layers of feldspar.

Question 5

A gem grader finds a natural inclusion that looks like a small crystal within a diamond. This inclusion is classified as a:

Accepted Answer

Crystal

Answer

A crystal inclusion is a mineral crystal trapped within a diamond during its formation, and it is classified as such in GIA clarity grading.

Gemology Certification Practice Test

Gemology Certification Practice Test

Gemology Certification Gemology Gemstone Grading & Evaluation 3