Red (hue / variety / modifier): Abbreviated (R). A perceived colour hue resembling the average colour of the gemstone ruby, ripe strawberries, or fresh blood. Red is a spectrum colour, positioned between orange and the infrared, in the 630 nm to 760 nm wavelength region. Red is also spoken of as being a warm colour. In the diamond trade, red represents one of the basic twelve colour varieties. Red diamonds can also contain secondary colour modifiers such as purplish red (pp-R), brownish red (br-R), orangish red (o-R), pinkish red (pk-R), and blackish red (bk-R). Red can also occur as a secondary colour modifier in other colour varieties such as reddish brown (r-BR), red-pink (R-PK), etc. The range of colour tone for red diamonds is small, limited in both lightness and saturation and includes pale (strawberry) red, dull (garnet) red, bright (ruby) red, and deep (cherry) red. Popular names for different mixtures of red are apple, autumn, blood, burgundy, cardinal, cherry, Chianti, china, claret, crimson, garnet, magenta, maroon, old rose, port, raspberry, rose, ruby, scarlet, strawberry, and tomato.