1.  turquoise(n = noun.substance) - a blue to grey green mineral consisting of copper aluminum phosphate; "blue turquoise is valued as a gemstone"
is a kind of mineral, opaque gem

2.  turquoise(n = noun.attribute) aqua, aquamarine, cobalt blue, greenish blue, peacock blue - a shade of blue tinged with green;
is a kind of blue, blueness

   A hydrous phosphate of alumina containing a little copper; calaite. It has a blue, or bluish green, color, and usually occurs in reniform masses with a botryoidal surface. [1913 Webster]
" Turquoise is susceptible of a high polish, and when of a bright blue color is much esteemed as a gem. The finest specimens come from Persia. It is also found in New Mexico and Arizona, and is regarded as identical with the chalchihuitl of the Mexicans." [1913 Webster]

   Having a fine light blue color, like that of choice mineral turquoise. [1913 Webster]

turquoise, n.
1 a semiprecious stone, usu. opaque and greenish- or sky-blue, consisting of hydrated copper aluminium phosphate.
2 a greenish-blue colour.

Etymology:
ME turkeis etc. f. OF turqueise (later -oise) Turkish (stone)

N  jewel, jewelry, jewellery, bijoutry, bijou, bijouterie, trinket, fine jewelry, costume jewelry, junk jewelry, gem, gemstone, precious stone, necklace, bracelet, anklet, earring, locket, pendant, charm bracelet, ring, pinky ring, carcanet, chain, chatelaine, broach, pin, lapel pin, torque, diamond, brilliant, rock, beryl, emerald, chalcedony, agate, heliotrope, girasol, girasole, onyx, plasma, sard, sardonyx, garnet, lapis lazuli, opal, peridot, tourmaline, chrysolite, sapphire, ruby, synthetic ruby, spinel, spinelle, balais, oriental, oriental topaz, turquois, turquoise, zircon, cubic zirconia, jacinth, hyacinth, carbuncle, amethyst, alexandrite, cat's eye, bloodstone, hematite, jasper, moonstone, sunstone, pearl, cultured pearl, fresh-water pearl, mother of pearl, coral, jeweler, gemologist, minerologist, lapidary, lapidarian, gemology, gemmology, minerology, bejeweled, diamond, (gemstones), gemological.

N  blueness, blue, garter-blue, watchet, ultramarine, smalt, cobalt, cyanogen, Prussian blue, syenite blue, bice, indigo, zaffer, lapis lazuli, sapphire, turquoise, indicolite, blueness, bluishness, bloom, blue, azure, cerulean, sky-blue, sky-colored, sky-dyed, cerulescent, powder blue, bluish, atmospheric, retiring, cold.