Black (hue / variety / modifier): Abbreviated (BK). A perceived colour hue resembling a lump of coal or the sky on a moonless night (i.e., midnight black). Black is the darkest colour sensation evident to the eye and the mind. A “nonspectral” colour the opposite of white, it is also a neutral (achromatic) colour lacking saturation, yet having a measurable range of lightness (L* = 00-10 =black approximately). The name black is derived from the Anglo-Saxon word blac, meaning dark. Popular names for different mixtures of black are charcoal, gun metal, ink, jet, midnight, and pitch. In the diamond trade, black represents one of the basic twelve colour varieties. Black diamonds can also contain secondary modifiers such as bluish black (b-BK), brownish black (br-BK), grayish black (gy-BK), greenish black (g-BK), olivish black (ol-BK), and purplish black (pp-BK). Black can also occur as a secondary colour modifier in other colour varieties such as blackish blue (bk-B), blackish brown (bk-BR), etc. Black is inherently dull in tone, yet individual black colours can vary in tone, resulting in pale (charcoal) black, dull (ink) black and bright (gun metal) black colours, all having weak saturation