"A variety of quartz which is peculiar in consisting of bands or layers of various colors blended together."-Whitney,…
A close-up, front view of the gold Alfred Jewel, which was made in the late 9th century. The inscription…
A close-up, side view of the gold Alfred Jewel, which was made in the late 9th century. The inscription…
"Determination of the optical character of a uniaxial crystal with the gypsum plate. Quartz (+)." -Johannsen,…
"Determination of the optical character of a uniaxial crystal with the gypsum plate when the center…
"Determination of the optical character of a biaxial crystal in a section cut perpendicular to the acute…
"Determination of the optical character of biaxial crystals in sections showing the emergence of an…
"Terminated usually by a combination of a positive and negative rhombohedron, which often are so equally…
"Terminated usually by a combination of a positive and negative rhombohedron, which often are so equally…
This illustration shows Quartz or Silica. Quarts is the most abundant mineral in the Earth's continental…
Well-rounded quartz grains from ancient eolian rock, enlarged by secondary addition of silica in optical…
Thin section of quartz sandstone shown under the microscope. The original rounded quartz grains are…
"The quartz crystals are said to be right or left handed, depending upon whether these faces are to…
"The quartz crystals are said to be right or left handed, depending upon whether these faces are to…