[aj-uh-lair-ee-uh] 
| a sometimes opalescent variety of orthoclase formed at a low temperature. |
| ad·u·lar·i·a (āj'ə-lâr'ē-ə, -lār'-) n. A variety of transparent or translucent orthoclase. [Italian, from French adulaire, after Adula, a mountain group of southeast Switzerland.] |
adularia
a feldspar mineral and potassium aluminosilicate (KAlSi3O8). It commonly forms colourless, glassy, prismatic, twinned crystals in low-temperature veins of felsic plutonic rocks and in cavities in crystalline schists. Typical occurrences include the schists of the Alps. Some adularia show an opalescent play of colours and are called moonstone.
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əˈlɛər