Cornelian
From Wikipedia, the free encyclopedia
 |
This article or section is in need of attention from an expert on the subject. Please help recruit one or improve this article yourself. See the talk page for details. Please consider using {{Expert-subject}} to associate this request with a WikiProject |
Cornelian is a red variety of chalcedony, which is cryptocrystalline quartz. Its red colour is due to the presence of iron impurities in the form of iron oxide or hematite. It can vary from a flesh red to a clear red. It is usually cut en cabochon, or into beads, and is also used for intaglios and cameos. Imitations of cornelian are made by the staining of agate. Cornelian is related to amethyst and citrine.
[edit] Sources
Originally found in the deserts of Arabia and Egypt, it has also been found in the Rio Grande area, India, China, Colombia, Saxony, Scotland, West Germany, and the USA.
[edit] Technical Details
- Chemical composition and name: SiO2 / Silicon Dioxide
- Hardness : 7
- Specific Gravity : 2.65 - 2.66
- Refractive Index (R.I.): 1.543 - 1.552 to 1.545 - 1.554
- Bi-refringence : 0.009
- Optic Sign : Positive
- Optical Character : Uniaxial
 |
This article about a specific mineral, mineraloid, or rock type is a stub. You can help Wikipedia by expanding it. |
