black diamond.

A dark grey or black diamondperhaps opaque, perhaps semi-transparent. The words are also used to describe carbonado, a tough industrial diamond.

—The Book of Diamonds by Joan Dickinson, 1965.

blue diamond.

Can be any shade of blue but diamonds that are blue in both daylight and incandescent light are rare; most show blue only in daylight. . . . The most famous blue is the Tavernier Blue or the French Blue, from which was cut the Hope Diamond.

—The Book of Diamonds, by Joan Dickinson, 1965.

brown diamond.

A reddish or coffee-brown fancy diamond, second in value among the fancies to yellow.

—The Book of Diamonds, by Joan Dickinson, 1965.

carbonado.

The toughest form of industrial diamond, usually black or gray and principally found in Brazil.

—The Book of Diamonds, by Joan Dickinson, 1965.

cellini green diamond and cellini peach diamond

These two diamonds of Frances I were described by Cellini as the most beautiful in the world. The Cellini Green, he said, was green like a pale green emerald but it shone as no emerald has ever shone. The Peach, which Cellini described as the second most beautiful, was flesh colored, tender, most limpid and it scintilated like a star.

—The Book of Diamonds, by Joan Dickinson, 1965.

champagne diamond.

A greenish yellow to yellow-green diamond of pronounced color.

—The Book of Diamonds, by Joan Dickinson, 1965.

fancy.

Any diamond with strong, attractive and natural body color. Red, blue, and green are the rarest.

—The Book of Diamonds, by Joan Dickinson, 1965.

fluorescence.

The property of changing one kind of radiation to another. Under X-ray, ultraviolet or cathode rays, the diamond usually fluoresces blue, although occasional stones may glow red or yellow shades. If the fluorescence is sufficiently strong to change the color of the stone for any length of time, it is called fluorochromatic.

—The Book of Diamonds, by Joan Dickinson, 1965.

golconda.

The Indian city that was the center of diamond trading in the seventeenth century, and as such a synonym for riches in the drama and poetry of this period. The term is often generously used to cover the ancient alluvial diamond deposits to the south and east of the city. . . .

—The Book of Diamonds, by Joan Dickinson, 1965.

green diamond.

A diamond with a naturally green color, a fancy. A stone turned green artificially should carry that information in its name. No naturally colored diamond of a true emerald green has yet been found, although Cellini claimed to have seen one in the fifteenth century.

—The Book of Diamonds, by Joan Dickinson, 1965.