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The first theme is using legendary luminous gems to illuminate buildings, for navigation lights on ships, or sometimes as guiding lights for lost persons (Ball 1938: 498–500). In India, the earliest country in which fine gemstones were known, belief in luminous gems dates back some twenty-five centuries.
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF 2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite.
Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple. [8] Topaz is a nesosilicate mineral, and more specifically, an aluminosilicate mineral. [9] It is one of the hardest naturally occurring minerals and has a relatively low index of refraction.
Strontium aluminate activated by europium, SrAl 2 O 4 :Eu (II):Dy (III), is a material developed in 1993 by Nemoto & Co. engineer Yasumitsu Aoki with higher brightness and significantly longer glow persistence; it produces green and aqua hues, where green gives the highest brightness and aqua the longest glow time.
Sodalite (/ ˈ s oʊ. d ə ˌ l aɪ t / SOH-də-lyte) is a tectosilicate mineral with the formula Na 8 (Al 6 Si 6 O 24)Cl 2, with royal blue varieties widely used as an ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite is a member of the sodalite group with hauyne ...
Rarely, it can be found as neon green or electric blue. Tourmaline ( / ˈtʊərməlɪn, - ˌliːn / TOOR-mə-lin, -leen) is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a wide variety of colors.
Lepidolite is a phyllosilicate mineral [ 5] and a member of the polylithionite-trilithionite series. [ 6] Lepidolite is part of a three-part series consisting of polylithionite, lepidolite, and trilithionite. All three minerals share similar properties and are caused because of varying ratios of lithium and aluminum in their chemical formulas.
Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluorescence, a phosphorescent material does not immediately reemit the radiation it absorbs.