Some minerals under ultraviolet ray lamps begin to glow and radiate with different color shades. If the minerals were glowing red, blue, green, or yellow, is the phenomenon of luminescence. The glow that is stopped immediately after turning off the lamp, is called fluorescence. And if it gradually and slowly fades, it phosphorescence.
The ability of minerals to the fluorescence due to the fact that their crystal lattice containing chemical elements luminogenic, and they give a glow minerals.
Such fluorescent minerals are metals from the group of iron - chromium, manganese, molybdenum, tungsten, uranium. Ions of chromium give a red glow, manganese - yellow-orange-red. This glow we see every day on television.
Property minerals to glow helps geologists in the search for these desired species. Using lamps-luminoscope in the United States ate found deposits Selimovic ores, which are tungsten. Green glow minerals uranium shows deposits of this important raw material. The smallest speck of uranium compounds are well visible in the dark under ultraviolet light. Diamondiferous kimberlite pipes help to detect apatites with violet-blue fluorescence. When extracting diamonds from crushed rock is used fluorescent electronic separators.
|Orange-red glow admixture of divalent manganese in calcite. So it glows in the halos of ore veins.|
|The blue glow of scheelite, which is indistinguishable to the naked eye, opened the largest in the world realitive deposits of tungsten.|
|Green glow uranium in ultraviolet rays - one of the most important search of signs of uranium ores.|
|On a bright yellow glow crystals and grains of zircon are defined in ores and placers.|
|A piece of zinc ore from deposits of polymetals Franklin (USA). Impurity ions of manganese gives a different glow color: yellow - wollastonite, purple in calcite. Organic impurities glow blue in the ore mineral hardystonite.|
|Bright blue fluorescence impurities of divalent europium in fluorite produced from rare metal veins.|
|(Illustration - "Science and life", No. 5, 1998)|