Carnelian – an orange-red kind of chalcedony. It was subjected to a facet and grinding in Ancient Egypt. The name is given mineral in honor of the town of Sarda in Lydia where it was for the first time found.
Origin
Carnelian, it a carnelian, – a chalcedony variation. And it, in turn, is a kind of quartz. The impregnations of oxide or hydroxide of iron distributed more or less evenly on all mineral give to carnelian an orange or red shade. This effect known in geology as colloidal dispersion, gives to a stone saturated color. Often in carnelian it is possible to see liquid droplets.
Carnelian meets in cavities of many rocks, especially volcanic origin. The majority of samples are formed of the fusions poor in silicon dioxide (for example, basalts) which stiffened on the earth's surface. Carnelian usually meets in the form of concretions and tumors and also stalactites.
Distribution
The most large-scale deposits of carnelian are located in India, especially on the Decanal plateau and also in Bengal and Ratnapura. Mineral of the Indian origin is famous for very saturated reddish-orange color which is partially caused by influence of beams of the sun.
Deposits of carnelian are also found in Brazilian Rio Grande do Sul, Uruguay, Saudi Arabia, Iran. In the Crimea, near the massif Kara Dag, there is a bay Serdolikovaya. There this mineral can be seen directly on the beach.
Properties
Carnelian – very solid mineral (6.5-7 points on Moos's scale). Its cost in original state is not so high. However the price grows many times after a facet and grinding. For these manipulations it is simply ideal thanks to the hardness and lack of a spaynost. The last property means that mineral does not break along fragile sides during processing.
Carnelian was actively used at a civilization dawn, did a jewelry, objects of a decor and small sculptures of it. The appeal of this mineral is concluded in unique coloring and ability to gain surprising gloss after polishing.
The facet is capable to give to carnelian almost any forms. Most often do beads and cabochons of this mineral. If carnelian is given the form with sides, then do them at an angle 40-45 degrees. The similar form of a facet meets infrequently as in it there is no sense: translucent mineral, but not reflective.
Carnelian imitation cases are frequent. For this purpose use colored glass and the painted chalcedony.
Quirky sellers give to faded samples of carnelian more saturated shade by soaking in orange dyes for a long time. The mineral is brighter, the it is more beautiful and the more expensively it is possible to sell it. However results of similar manipulations will not deceive an eye of the experienced specialist in stones.