Colourless and near-colourless diamonds are sometimes referred to as "white," in contrast to fancy-colour diamonds, but among the fancy colours is a rare appearance described as Fancy White Diamonds.

White diamonds have a perceived colour hue resembling snow, refined sugar, or pasteurized whole milk. Such diamonds contain a high concentration of submicroscopic inclusions that scatter light, yielding a translucent "milky" white face-up colour. The nature of these inclusions is unknown.

White is the lightest colour perception evident to the eye and the mind. White is also known as a neutral (achromatic) colour having no saturation yet having a measurable range of lightness.

Popular names for different mixtures of white are cream, ivory, milk, moonstone, opalescent, pearl, salt, snow and sugar.

Fancy white diamonds are diamonds with a milky white colour, similar like white moonstone. They contain minute particles which scatter the light, thus leave the stone slightly turbid white.

These diamonds are often called "opalescent" because the dispersion of the stones looks somewhat like the play of colour of opals. These diamonds are very rare, as rare as pinks or certain blues, but normally not very attractive and much, much cheaper. The stones are usually very hydrogen rich diamonds (pure type laB).

White diamonds can have a brownish, bluish, yellowish and grayish appearance.