Colour filters allow observations in the range of special wavelengths, e.g. in the red range at 690 nm and in the yellow range at 570 nm. The view through the filters lets some stones appear in different colours and helps to distinguish between gemstones. These filters are also a valuable tool in the assessment of gemstone lots.
■ Gray painted metal housing with optical glass
■ Filter glass: Ø 18 mm
■ Dimensions (W × W): 45 mm x 50 mm
■ Weight: approx. 21 g
You can find practical examples of the use of color filters in the article: Discovering fakes with color filters.
More information on the examination method with the Chelsea filter or with the ruby filter can be found in the Color filter method article.