Chameleon turquoise, and purple. Chameleon skin has a superficial layer which contains pigments, and under the layer are cells with guanine crystals. Chameleons change colour by changing the space between the guanine crystals, which changes the wavelength of light reflected off the crystals which changes the colour of the skin. Colour change in chameleons has functions in camouflage, but most commonly in social signaling and in reactions to temperature and other conditions. The relative importance of these functions varies with the circumstances, as well as the species. Colour change signals a chameleon's physiological condition and intentions to other chameleons. Chameleons tend
Buff (colour) century, the traditional colour of formal dress boot uppers was often described as "buff". Clothing depicted on John Bull, a national personification of Britain in general and England in particular, in political cartoons and similar graphic works, has often been buff coloured. Bull's buff waistcoats, topcoats, trousers and boot uppers were typical of 16th- and 17th-century Englishmen. Buff is a traditional European military uniform colour. Buff has good camouflage qualities as sand, soil, and dry vegetation are buff in many areas. The term "buff coat" refers to a part of 17th-century European military uniforms. Such coats were intended to protect