Questionaire 2

An area of weak saturation in a transparent gemstone's bodycolor that usually results from the way the gem was cut is

A window. - Windows are usually caused by light leaking out through the bottom of the stone.

Color is born from an interaction between light, and object, and

An observer - Color requires the interaction of light, an object, and an observer.

Star ruby shows a phenomenon called

Asterism. - The star phenomenon seen in some gems is called asterism.

A gem's basic color is known as its

Bodycolor. - A gemstone's bodycolor is determined by its selective absorption of light.

The trade term used to describe orangy red topaz is

imperial.

Areas of different color in a gem, caused by variations in growth conditions, is called

Color zoning - Color zoning can occur when a gem crystal recieves differing amounts of color-causing nutrients as it grows.

The separation of white light into spectral colors is called

Dispersion. - The colorful display caused by dispersion is called "fire".

Each of the colors that make up white light is called a spectral

Hue. - Some hues are "pure", while others are combination of hues.

Gems that display unusual optical effects are classified as

Phenomenal. - The striking optical effects of phenomenal gemstones set them apart as unique and help determine their value.

The shifting flashes of rainbow hues seen in opals are known as

Play-of-color. - Play of color in opal occurs as a result of it's unusual structure.

A gem that shows different bodycolors depending on the viewing direction is

Pleochroic. - Pleochroic gems show different bodycolors from different viewing directions.

A color's strength or intensity is called its

Saturation. - Highly saturated colors look vivd and intense. Greens, blues, and violets with low saturation look grayish, while reds, oranges, and yellows look brownish.

Alexandrite shows color change in response to

The type of light - Fine alexandrite looks purplish red in incandescent light, such as the light from a standard light bulb. When viewed in fluorescent light or sunlight, it appears green or bluish green.

The lightness or darkness of a color is called its

Tone. - The degree of darkness or lightness of a color is its tone.