Product Description
The Chelsea filter allows transmission of both deep-red wavelengths around 690 nanometers and yellow-green wavelengths around 570 nanometers. These wavelengths correspond to the absorption and emission characteristics of emerald. When a natural emerald is viewed through the filter, it will appear red or reddish-green. This is because the emerald absorbs the red light, while the yellow-green light is transmitted.
Stimulants of emerald, such as green glass, will not appear red or reddish-green when viewed through the Chelsea filter. This is because they do not absorb red light in the same way that emeralds do. Instead, they will appear green, yellow, or orange.
The Chelsea filter can also identify certain red and blue stones. For example, natural rubies will appear red when viewed through the filter, while synthetic rubies will appear orange or pink. Natural sapphires will appear blue when viewed through the filter, while synthetic sapphires will appear green or yellow.
