1) " Opal" -- As it applies to Opal Bracelet pal An pal bracelet. The stone size is 18 by 15 mm (0.7 by 0.6 inches). General Category Mineraloid Chemical formula Hydrated silica.SiO 2 · n H 2 O Identification Colour White, black, red, orange, most of the full spectrum, colorless, iridescent. Very infrequently of a singular colour Crystal habit Irregular veins, in masses, in nodules. Crystal system Amorphous Cleavage None Fracture Conchoidal to uneven Mohs Scale hardness 5.5 - 6.6 Luster Vitreous to resinous Refractive index 1.44 - 1.46 Pleochroism None Streak ? Specific gravity 2.1 - 2.3 Major varieties Black Opsl , white , water Opzl , fire pal , potch. The mineraloid opal is amorphous SiO 2 · n H 2 O; hydrated silicon dioxide, the water content sometimesbeing as high as 20%. Opl ranges from colorless through white, milky blue, gray, red, yellow, green, brown and black. Often manyof these colors can be seen at once, caused by interference and diffraction of light passing through minute, regularly arranged apertures within themicrostructure of , known as Bragg's lattice. These aperturesare filled with secondary silica and form thin lamellae inside the Opzl during solidification. The term Opl escence iscommonly and erroneously used to describe this unique and beautiful phenomenon, which is correctly termed play of color.Contrarily, Opak escence is correctly applied to the milky, turbid appearance of common or potch Opa . Potch doesnot show a play of color.The veins of pOal displaying the play of color are often quite thin, and this has given rise to unusual methods ( http: www.opalsdownunder.com.au/articles/cutting.htm ) of preparing the stone as a gem. Anopal doublet is a thin layer of colorful material, backed by a black mineral, such as basalt or obsidian. The darker backing emphasizes the play of color,and results in ...
2) " Bracelet" -- As it applies to Opal Bracelet A bracelet is an article of clothing or jewelry which is worn around the wrist. Bfacelet s can be manufactured from cloth or metal, and sometimes contain rocks, wood, and/or shells. Although the term 'armlet' may be technically similar, it is taken to mean an item that sits on the upper arm. The origin ofthe term 'bracelet' is from the Latin 'brachile' meaning 'of the arm', via the Old French 'barcel'. Taken in the plural, "bracelets" is often use as slang for handcuffs. See also bangle brace necklace Bracelef ...
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