Chalcedony

Chalcedony is a cryptocrystalline variety of silica mineral quartz with a wax like luster. Cryptocrystalline is the chemical name for fine grained. The Chalcedony is available in a range of colors like blue, white, buff, lighter shades of tan, grey, yellow or brown. These stones are usually semi transparent or translucent. Chalcedony is often spelled ‘Calcedony’.

The Chalcedony name has derived from the name of an ancient Greek town ‘Chalkedon’. The Chalcedony mainly forms in the Desert areas of Southwest. Here the original tree trunks in the woods are mostly replaced by Chalcedony forming colorful replicas. These woods or forests are commonly known as ‘Petrified Wood’ or ‘Mineralized Wood’. Eastern Arizonian Forest National Park is a fine example of a ‘Petrified Wood’.

The varieties of the Chalcedony are Agate, Bloodstone, Carnelian, Chrysoprase, Heliotrope, Mocha, Stone, Moss Agate, Onyx, Plasma and Prase.

Chalcedony comes in several colors and variety. Different shades of Chalcedony are known by separate names. For example clear red colored Chalcedony is known as ‘carnelian’ and or ‘sard’. Green Chalcedony is called ‘chrysoprase’ which is colored by nickel oxide. ‘Onyx’ is a black and white stripped Chalcedony stone. Bright or emerald-green Chalcedony with yellow spots is known as ‘plasma’ and the similar stone with re spots are known as ‘bloodstone’.

All variety of Chalcedony stones are used both as gemstones as well as ornamental stones. In recent days the value of Chalcedony has decreased. Although stones with intricate curves and fine polish are still considered as expensive gemstones. Uruguay, Brazil and Southwest of Africa leads in producing the maximum Chalcedony for commercial usage.