turquoise

noun

1. (countable)A sky-blue, greenish-blue, or greenish-gray semi-precious gemstone.

   “Although there are dozens of different types of gems, among the best known and most important are […] . (Common gem materials not addressed in this article include amber, amethyst, chalcedony, garnet, lazurite, malachite, opals, peridot, rhodonite, spinel, tourmaline, turquoise and zircon.)”

2. (countable, uncountable)A pale greenish-blue colour, like that of the gemstone.

   “The half-dozen pieces […] were painted white and carved with festoons of flowers, birds and cupids. To display them the walls had been tinted a vivid blue which had now faded, but the carpet, which had evidently been stored and recently relaid, retained its original turquoise.”

adj

1. Made of turquoise (the gemstone).
2. Having a pale greenish-blue colour.