Abstract
A granodiorite gneiss in the central Wind River Range, Wyoming contains numerous veins of blue, opalescent quartz (Parker, 1962) which owes its blue color to scattering of light by tiny needles of tourmaline. The color of blue quartz has been attributed to the presence of minute rutile needles by a number of authors (Goldschmidt, 1954; Holden, 1923; Lukesh, 1945; Watson and Beard, 1917.) Gordon (1946) attributes the blue color to “blue needles” which he identifies as trains of minute bubbles. Goldschmidt (1954) states that blue, rutile-bearing quartz is not to be confused with Cambrian and Ordovician blue quartzites of Norway which owe their color to fine, disseminated magnetite dust. Boyle (1953) notes the presence of graphite in certain black and gray quartz from Canada.