Abstract: The control knob engages, on its interior, a translucent polycarbonate jewel body collar assembly of a first color, such as white, which, in turn, provides a housing for a translucent polycarbonate jewel LED holder assembly. The LED emits light, possibly modified by the jewel LED holder assembly, of a second color, such as blue or blue-green. This second color can be varied in intensity and hue by varying the polarity and resistance of the LED. The jewel body collar assembly includes a collar to engage the interior cylindrical support section of the control knob and a housing assembly to engage the jewel LED holder assembly. The jewel body collar assembly further includes a ridge which protrudes through a slot in the sidewall and front face of the control knob thereby forming an indicator for the control knob. In ambient illumination, such as during the day, the indicator appears to be the color of the jewel body collar assembly, such as white.