Chalcedony /kaelËsÉdÉni/ kÃ¦lËsÉdÉni is a cryptocrystalline form of, silica composed of very fine intergrowths of the minerals quartz and. moganitehese are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic. Chalcedony's standard chemical structure (based on the chemical structure of quartz) is SiO 2 (silicon dioxide). Chalcedony has a waxy luster, and may be semitransparent or translucent.
For more than 2,000 years, the Hopi have lived in what is today known as the Four Corners region where Arizona, New Mexico, Utah, and Colorado meet. Their reservation, located in northeastern Arizona, occupies about 1.5 million acres, comprising only a small portion of their traditional lands.
Hopi ceremonial practice is governed by the belief in the absolute interdependent relationship between the upper and lower worlds. Day and night, summer and winter alternate between the two realms. It is believed that when people are born they emerge out of the lower world and when they die their souls descend into the lower world.