orange diamond.
A diamond of distinct orange tint but also probably a diamond from the Orange River area in South-West Africa where most of these bright and sometimes flaming fancies are found.
—The Book of Diamonds, by Joan Dickinson, 1965.
philosophers stone.
An imagined, long searched for, never discovered stone which was believed by medieval alchemists to have the power to change rock or flint into gold or diamond.
—The Book of Diamonds, by Joan Dickinson, 1965.
phosphorescence.
The property of continuing to emit visible light in darkness after exposure to radiation. Some diamonds (like many squid) do it, but they are unusual diamonds.
—The Book of Diamonds, by Joan Dickinson, 1965.
photoluminescence.
The property of some diamonds and other gems to become luminescent when exposed to the action of visible or ultraviolet-light rays only. They are said to be fluorescent if luminescent during exposure, and photophorescent if luminescent or glowing afterwards.
—The Book of Diamonds, by Joan Dickinson, 1965.
pink diamond.
A light-red diamond, more reddish than peach colored, less rosy than rose colored, and less purle than heliotrope. A fancy.
—The Book of Diamonds, by Joan Dickinson, 1965.
premier diamond.
A diamond that changes color from blue to yellow depending on whether the light is daylight or incandescent light.
—The Book of Diamonds, by Joan Dickinson, 1965.
red diamond.
The rarest of all fancy-colored diamonds are red ones, and so any red-brown or rose-colored diamond is often called a red diamond. No really ruby-colored diamonds have ever been reported.
—The Book of Diamonds, by Joan Dickinson, 1965.
rhinestone.
The name now given to colorless lead-glass brilliant-cut or single-cut imitation diamond. Once rhinestone was only applied to colorless quartz crystals from the Rhine River valley in Germany; when highly dispersive glass became available, it was substituted for the quartz.
—The Book of Diamonds, by Joan Dickinson, 1965.
rose cut.
An early style of cutting. It is usually rose shaped, that is, it has a flat base, and a domelike top with a variety of triangular facets resembling petals which come to a small point at the center like a rosebud. Also called a rosette.
—The Book of Diamonds, by Joan Dickinson, 1965.
scintillation.
The flashing or twinkling of light which in diamonds comes from the facets. Comparative scintiallation of two diamonds can be measured by the number of facets on the stone and the quality of their polish.
—The Book of Diamonds, by Joan Dickinson, 1965.