Blue-green much larger color gamut than RYB color space. The first recorded use of "cyan" as a color name in English was in 1879. The color turquoise, a representation of the color of the semi-precious stone turquoise. The first recorded use of "turquoise" as a color name in English was in 1573. The color "turquoise" is a light tone of blue-green. Green-blue had been a Crayola color since 1958. It was continued as a Crayola crayon color until 1990. One definition of the color is in the Munsell color system (Munsell 5BG) although there is wide-spread acceptance and knowledge of the
RG color space replicated accurately in the RG color space. There is a similar color space called RGK which also has a black channel. Outside of a few low-cost high-volume applications, such as packaging and labelling, RG and RGK are no longer in use because devices providing larger gamuts such as RGB and CMYK are in widespread use. Until recently, its primary use was in low-cost light-emitting diode displays, where red and green tended to be far more common than the still nascent blue LED technology, though full-color LEDs with blue have become more common in recent years. ColorCode 3-D, a stereoscopic color