White (hue / variety / modifier): Abbreviated (WH). A perceived colour hue resembling snow, refined sugar, or pasteurized whole milk. (See Figs. 9.4 & 9.5.) White is the lightest colour perception evident to the eye and the mind. It is a “nonspectral” colour, the opposite of black. White is also known as a neutral (achromatic) colour having no saturation, yet having a measurable range of lightness (L* = 100- 90 = white approximately). Popular names for different mixtures of white are cream, ivory, milk, moonstone, opalescent, pearl, salt, snow, sugar, and tiffanyite. In the diamond trade, white represents one of the basic twelve colour varieties. White diamonds can also contain secondary modifiers such as brownish white (br-WH), bluish white (b-WH), grayish white (gy-WH) and yellowish white (y-WH). White can also occur as a secondary colour modifier in other colour varieties such as whitish gray (wh-GY), white-brown (WH-BR), etc. White is inherently pale in tone, yet individual white colours can vary in tone resulting in pale (snow) white, bright (moonstone) white and dull (ivory) white colours, all having weak saturation. In the commercial diamond trade, the name white is frequently used as a descriptive term to denote colourless diamonds that appear white to the unaided eye in the face-up direction (i .e., commercial white). In this context, the colourless stone does not contain an inherent whiteness in its body colour such as that exhibited by a translucent white diamond. In a colourless diamond, the observer sees theimage of a white light source that is wholly or partly reflected in the facets of a well-proportioned diamond in the face-up direction. (See Fig. 9.8.) Thus, for the collector, it is more appropriate to refer to the so-called commercial white diamonds as colourless (or near colourless), which distinguishes them from the translucent white variety