1 - Basic Terms Flashcards
Which elements are diamonds composed of?
Carbon
Four Cs
Color, Clarity, Cut, Carat weight
Baguette
A small, four-sided step cut that’s rectangular, square, or tapered.
Blemish
Clarity characteristic that’s confined to the surface of a polished gemstone.
Branded cut
Cutting style that’s developed, named, and promoted by a specific manufacturer.
Brightness
The effect of all the diamond’s internal and external reflections of white light.
Brilliant cut
Cutting style with triangular or kite-shaped facets that radiate from the center toward the girdle. Very popular.
Clarity characteristics
The collective term for inclusions and blemishes.
Crown
Top part of the gem above the girdle.
Culet
Small facet at the bottom of a finished gem.
Durability
A gemstone’s ability to withstand wear, heat, and chemicals (also known as hardness, toughness, and stability.)
Facet
A flat, polished surface on a finished gem.
Fancy cut
Any gemstone shape or cutting style other than a standard round brilliant.
Fire
The flashes of color you see in a polished diamond.
What is the girdle and what is its function?
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.
Hardness
How well a gemstone resists scratches and abrasion.
Inclusion
Clarity characteristic totally enclosed in a polished gemstone or extending into it from the surface.
Karat
A unit of measurement for the fineness of gold, abbreviated K or Kt.
Lab-grown gem
A manmade (synthetic) gem with essentially the same chemical composition, crystal structure, and properties as its natural counterpart.
Metric carat
The international unit of measurement for gem weight. One carat = 0.2g
Mixed cut
Cut that combines brilliant-cut and step-cut styles.
Mohs scale
Ranking of the relative hardness of 10 minerals.
Point
1 point = .01ct
Scintillation
The flashes of light and the contrasting dark areas you see when the diamond, the light, or the observer moves.
Simulant
A natural or manmade material that resembles a gem (also called imitation.)
Single cut
A round stone with 17-18 facets.
Stability
How well a diamond resists chemicals and temperature changes.
Standard round brilliant
A round brilliant-cut stone with 57-58 facets. Often called a full cut.
Step-cut
A cutting style that features long, narrow facets in rows parallel to the girdle on both the crown and pivilion.
Thermal shock
Damage caused by sudden, extreme temperature changes.
Toughness
How well a gemstone resists breaking and chipping.
Value factors
Features used to judge the quality and value of all gemstones.
How do the Four Cs influence diamond value?
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.
What is the most popular simulant for diamonds?
Cubic zirconia and synthetic moissanite.
Describe a diamond’s hardness, toughness, and stability.
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.
