Quartz Varieties

Varieties

• Quartz is classified as either crystalline (also called macrocrystalline) or cryptocrystalline (sometimes called microcrystalline). Crystalline quartz is characterized by its large glasslike composition or crystals. Pure crystalline quartz is colorless and is referred to as rock crystal. However, there are many other colored varieties including amethyst. Cryptocrystalline quartz is distinguished by its dense, rocklike structure, because unlike crystalline quartz, its crystal components are microscopic. Traditionally, cryptocrystalline quartz has been described as either fibrous or microgranular. Examples of cryptocrystalline quartz include jasper and chalcedony.

Rock Crystal

• Rock crystal, also called quartz crystal, is highly valued for its transparency, translucency (colorlessness) and clarity (lack of flaws). It's been used as a gemstone and as a base to artificially create other gemstones, such as versions of topaz and smoky quartz via radiation heat treatments. This crystalline quartz has been a component of various religious, ornamental, architectural structures for centuries. Because of rock crystal's piezoelectric properties, it has also been used in scientific applications to control radio frequency transmissions and other electrical circuit oscillations. There are rock crystal mines located throughout the world including sites in the United States, Mexico, Russia, China, Nambia, Australia and Norway.

Amethyst

• Amethyst is one of the most widely known gemstone quartz, crystalline varieties in the world. Its name is derived from Greek, meaning "non-drunkenness," which pertains to the ancient belief that amethyst protects its owners from the intoxicating effect of alcohol.

  Amethyst generally ranges in color from violet to purple; however, there are numerous variations that include pink, red and gray. At one time, the majority of mined amethyst came from India, Germany, Sri Lanka and Russia. However, due to geological advances, amethyst is now mined and even cultivated worldwide, with major supplies also mined in Uruguay, Brazil and North America.

Jasper

• Jasper is an opaque, microgranular variety of microcrystalline quartz. Technically, jasper is not a mineral but instead, is a mixture of various types of microcrystalline quartz and other mineral impurities. While red jasper is widely known and used as a gemstone, other colors including brown, green yellow and multicolored (or ribbon) jasper are utilized for ornamental purposes. Jasper is mined worldwide.

Chalcedony

• Chalcedony is a fibrous, somewhat translucent cryptocrystalline variety of quartz, mined on almost every continent throughout the world. It is also a catchall term used to describe many forms of cryptocrystalline quartz. While pure chalcedony looks blue, gray or white, illumination causes its appearance to become reddish. Other quartz varieties, such as chrysoprase, carnelian, sard, onyx, agate, bloodstone and sardonyx, are all forms of chalcedony.

  Chalcedony was used as one of mankind's first raw materials for making various items including tools, weapons, containers and utensils.