Agate is a translucent variety of micro crystalline quartz. It is used as a semiprecious stone when it is of desirable quality and color. Agate generally forms by the deposition of silica from groundwater in the cavities of igneous rocks. The agate deposits in concentric layers around the walls of the cavity, or in horizontal layers building up from the bottom of the cavity. These structures produce the banded patterns that are characteristic of many agates.
Agate occurs in a wide range of colors, which include brown, white, red, gray, pink, black, and yellow. The colors are caused by impurities and occur as alternating bands within the agate. The different colors were produced as ground waters of different compositions seeped into the cavity. The banding within a cavity is a record of water chemistry change. This banding gives many agates the interesting colors and patterns that make it a popular gemstone.
Metaphysically, Agate has a lower intensity and vibrates to a slower frequency than other stones, but is highly regarded as a stabilizing and strengthening influence. The layered bands of microscopic quartz in Agate may appear delicate, they are actually very strong. Agate is excellent for balancing emotional, physical and intellectual energy, and in harmonizing yin and yang, the positive and negative forces of the universe.