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.