The chemical formula of mineral Chalcedony is indicated by SiO2 or Silicon Dioxide. Chalcedony actually occurs in every imaginable color that appears more fascinating under polarizing light microscope used in optical mineralogy. Chalcedony is commonly found leaving a white streak when rubbed on a white porcelain streak plate. The hardness measure of the mineral when it is evaluated using the Mohs scale method is usually 7. Chalcedony is known to crystallize in the hexagonal system of crystal formation. In optical mineralogy, the hexagonal system of crystallization comprises crystals having four axes. Three of which are positioned in a single plane with equal length and are symmetrically spaced. The fourth axis is found to be perpendicular to the other three axes. It is however important to note that Chalcedony, being a microscrystalline variety of quartz does not occur in crystals. It is commonly found occurring in botryoidal, mammilary, stalatitic, massive, nodular, as smooth rounded peebles, as banded, and in geodes. Most Chalcedony crystals are found transparent to opaque in appearance. The specific gravity measure of Chalcedony is usually found ranging from 2.6 to 2.7 grams per cubic centimeters.

 

            Chalcedony is usually found showing vitreous, waxy, or dull luster when viewed in reflected light of polarizing microscope used in the field of optical mineralogy. Some yellow or brown varieties however are found resinous. Chalcedony has no cleavage found even when it is closely evaluated with the aid of petrographic polarizing microscope used in optical mineralogy. Chalcedony is usually found showing conchoidal fracture when viewed under polarized microscopes. It also has brittle tenacity. Many Chalcedony specimens found that fluoresce, usually green or white color that appears very interesting. Chalcedony is also found showing tribolumininescent effect as well as piezoelectric. Scientifically, the term Chalcedony refers to any type of microcrystalline Quartz. However, in the gem trade it describes a common white or lightly colores nodular or massive type.

             Chalcedony is not really known by its name. It is actually called by scientists as Microcrystalline Quartz, and most collectors and gem dealers actually call each variety by its particular name. There is another variety called Agate, the most varied and popular of all Chalcedony. This variety of Chalcedony is extremely abundant and commonly creates unusual and stunning examples when viewed under polarizing light microscope used in optical mineralogy. In its natural state however, Agate appears ugly and needs to be trimmed and polished to bring out their full beauty and fascinating appearance. It can be found more splendid and wonderful when evaluated with the aid of petrographic polarizing light microscope used in the field of optical mineralogy. Some Chalcedony is porous and it can be possibly dyed different colors. Many of this variety are found in Brazil. Some Chalcedony is sometimes found in geodes. They are usually found lining the mammilary blobs. Chalcedony frequently pseudomorphs after organic materials. A well-known example is petrified wood, wood that has been completely transformed into Chalcedony. Another Chalcedony pseudomorphs is the famous Tiger’s Eye. This variety is almost legendary and has the most interesting and confusing appearance when viewed under petrographic polarizing light microscope used in the field of optical mineralogy. The most striking features of Chalcedony include hardness and form. It is also known to be soluble in hydrochloric acid. The hardness and crystal habits of Chalcedony distinguish it from all minerals. Chalcedony occurs in virtually all mineral environments. It may be associated with almost every mineral.