The Gemax Chelsea Filter is a tool used by geologists and gemologists to identify and classify minerals and gemstones. The filter works by selectively filtering out certain wavelengths of light, allowing the user to see the specific color or range of colors that are characteristic of a particular mineral or gemstone. The filter is named after its inventor, Sir Charles H. F. Chelsea, who developed the original Chelsea Filter in the early 20th century. The Gemax Chelsea Filter is an updated version of the original, with a more durable design and improved optical properties.
The filter is made up of two glass filters, one blue and one yellow, which are held together in a metal frame. When light passes through the filters, certain colors are absorbed by the glass, while others are transmitted through to the eye. This selective filtering allows the user to see the characteristic colors of certain minerals and gemstones, which can help with identification and classification. The Gemax Chelsea Filter is particularly useful for identifying emeralds, as it can differentiate between natural and synthetic stones. Natural emeralds will appear red through the filter, while synthetic stones will appear a shade of pink. The filter can also be used to identify other minerals, such as chromite, which appears a bright red through the filter. Overall, the Gemax Chelsea Filter is a valuable tool for anyone working with minerals or gemstones, as it can provide important information for identification and classification.