Noun

(en noun)

(mineral) Any of a large group of rock-forming minerals that, together, make up about 60% of the earth's outer crust. The feldspars are all aluminum silicates of the alkali metals sodium, potassium, calcium and barium. Feldspars are the principal constituents of igneous and plutonic rocks.

Noun

(en noun)

A sky-blue, greenish-blue, or greenish-gray semi-precious gemstone.

* {{quote-magazine, date=2012-03

, author=Lee A. Groat , title=Gemstones , volume=100, issue=2, page=128 , magazine=(American Scientist) citation , passage=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.)}}

A pale greenish-blue colour, like that of the gemstone.

* {{quote-book, year=1963, author=(Margery Allingham)

, title=(The China Governess) , chapter=1 citation , passage=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 .}}