Hairline cracks in precious stones become visible under UV light. Most people know artificial UV light from the solarium, the disco or the loading funds to the examination of bank notes. This latter possibility of identification should also here we are interested in relating to minerals. The general effect that Ultraviolet light causes of materials is the glowing. Starting from otherwise not even glowing materials such as minerals through inner photo-physical processes to shine. UV light stimulates the molecular grid structure of minerals to the swing. Of this unused part of the light energy radiating back as long-wave and now visible, coloured light. So allow lamps, which emit about short-wave UV, the identification of uranium-containing rocks, such as the search for fluorite and calcite.

Calcite lights usually various shades of red. In the metallurgy in metal mining, the measurement of different fluorescent light of ore plays an important role. Here also UV lasers are used. Good usable ores and industrial minerals fluoresce significantly stronger than low-grade ores. It is different then in the limestone: iron deposits it can prove this in turn reduces the value of the natural stone. Detecting precious stone fakes and repairs which mentioned the ability of molecular structures, to change the light in different ways in the wavelength and characteristic to visualize, offers more application possibilities in the mineralogy. So, some gems on their authenticity can be verified. Synthetically produced precious stones fluoresce less or different characteristic, so that counterfeiting of genuine stones may be distinguished.

UV light clearly is also very fine, otherwise invisible hairline cracks in a gemstone. Hereby, the value of a jewel can be prized better. Of course, precious stone traders attempt to repair any defects. Adhesives and liquid resins, placed in the stone can appear intact and optically pure stone in normal light. Similar to the car glasses also at repair of small damages in one go Windshield before. But such foreign matter never exactly break the UV-light and forward as the surrounding original material, are such repair places under UV light. Suitable UV light equipment for the Mineralogical interested come home appropriate hand and also stand lamps into consideration. These should have the selectable choice of short and long-wave UV light. Some minerals can be only with short or long-wave UV light to the glowing. This gives even more differentiation possibilities. Mains-independent and portable UV lamps are ideal for a search on the spot. So, certain minerals in a rock quarry can be first found about at night. During daylight hours small boxes are useful outside of an abdunkelbaren room equipped with UV light and in which rock samples on the ground while avoiding other light can be analysed. The design of merchandisers is a fascinating hobby for collector of minerals: equipped with suitable UV lamp, mounted a start in the showcase suitable minerals in different colors to light up. However, care must be taken in dealing with UV light: sustained direct radiation is harmful to eyes and skin, as we know from the solarium. About goggles is recommended when direct dealing with UV lamps.