1 - Basic Terms

Question 1

Which elements are diamonds composed of?

Answer 1

Carbon

Question 2

Four Cs

Answer 2

Color, Clarity, Cut, Carat weight

Question 3

Baguette

Answer 3

A small, four-sided step cut that’s rectangular, square, or tapered.

Question 4

Blemish

Answer 4

Clarity characteristic that’s confined to the surface of a polished gemstone.

Question 5

Branded cut

Answer 5

Cutting style that’s developed, named, and promoted by a specific manufacturer.

Question 6

Brightness

Answer 6

The effect of all the diamond’s internal and external reflections of white light.

Question 7

Brilliant cut

Answer 7

Cutting style with triangular or kite-shaped facets that radiate from the center toward the girdle. Very popular.

Question 8

Clarity characteristics

Answer 8

The collective term for inclusions and blemishes.

Question 9

Crown

Answer 9

Top part of the gem above the girdle.

Question 10

Culet

Answer 10

Small facet at the bottom of a finished gem.

Question 11

Durability

Answer 11

A gemstone’s ability to withstand wear, heat, and chemicals (also known as hardness, toughness, and stability.)

Question 12

Facet

Answer 12

A flat, polished surface on a finished gem.

Question 13

Fancy cut

Answer 13

Any gemstone shape or cutting style other than a standard round brilliant.

Question 14

Fire

Answer 14

The flashes of color you see in a polished diamond.

Question 15

What is the girdle and what is its function?

Answer 15

The narrow section of a finished gem that forms the boundary between the crown and the pavilion and functions as the gem’s setting edge.

Question 16

Hardness

Answer 16

How well a gemstone resists scratches and abrasion.

Question 17

Inclusion

Answer 17

Clarity characteristic totally enclosed in a polished gemstone or extending into it from the surface.

Question 18

Karat

Answer 18

A unit of measurement for the fineness of gold, abbreviated K or Kt.

Question 19

Lab-grown gem

Answer 19

A manmade (synthetic) gem with essentially the same chemical composition, crystal structure, and properties as its natural counterpart.

Question 20

Metric carat

Answer 20

The international unit of measurement for gem weight. One carat = 0.2g

Question 21

Mixed cut

Answer 21

Cut that combines brilliant-cut and step-cut styles.

Question 22

Mohs scale

Answer 22

Ranking of the relative hardness of 10 minerals.

Question 23

Point

Answer 23

1 point = .01ct

Question 24

Scintillation

Answer 24

The flashes of light and the contrasting dark areas you see when the diamond, the light, or the observer moves.

Question 25

Simulant

Answer 25

A natural or manmade material that resembles a gem (also called imitation.)

Question 26

Single cut

Answer 26

A round stone with 17-18 facets.

Question 27

Stability

Answer 27

How well a diamond resists chemicals and temperature changes.

Question 28

Standard round brilliant

Answer 28

A round brilliant-cut stone with 57-58 facets. Often called a full cut.

Question 29

Step-cut

Answer 29

A cutting style that features long, narrow facets in rows parallel to the girdle on both the crown and pivilion.

Question 30

Thermal shock

Answer 30

Damage caused by sudden, extreme temperature changes.

Question 31

Toughness

Answer 31

How well a gemstone resists breaking and chipping.

Question 32

Value factors

Answer 32

Features used to judge the quality and value of all gemstones.

Question 33

How do the Four Cs influence diamond value?

Answer 33

Clarity: Clarity’s influence on value is directly related to the concept of rarity. The increase in value per increasing step in clarity is not linear.

Color: Diamonds attempting to approximate a colorless diamond will be more valuable for each color grade up. Rare colors are red, purple, and green - for these, more color means higher value. Size makes a difference in how obvious a color is.

Cut: A cut that enhances brilliance fire, and scintillation will have more value. Some special and branded cuts are more expensive due to their difficulty or copyrighted nature.

Carat: Large diamonds cost more not just because of the higher carat value, but because the price per carat increases with the size of the diamond due to the rarity of large diamonds.

Question 34

What is the most popular simulant for diamonds?

Answer 34

Cubic zirconia and synthetic moissanite.

Question 35

Describe a diamond’s hardness, toughness, and stability.

Answer 35

Diamonds are a 10 on the Mohs Scale, meaning diamonds are the hardest gemstone.
Diamonds will fracture if a hard blow hits a cleavage direction. Toughness is particularly related to cut features and shape (thin girdles, pears, marquises = less tough)
Diamonds are very stable. They are invulnerable to virtually all acids and withstand heat well. Vulnerable to thermal shock.