Quartz

Quartz (named after a Slavic word for 'Hard') is the name for a group of minerals of the same chemical composition (SiO₂) and similar physical properties. Different names are given to quartz based on microstructure of the mineral and color. Few of the common quartz varieties are Rock Crystal, Smoky Quartz, Amethyst, Citrine, Prasiolite, Rose Quartz, Aventurine, Prase, Blue Quartz, Cat's Eye, Hawk's eye, Tiger's eye, Chalcedony, Carnelian, Sard, Chrysoprase, Bloodstone, Dendritic Agate, Moss Agate, Agate, Jasper.

 

Rock Crystal

Clear and color less stone, found in Brazil, Madagascar, the United States and the Alps. Rock crystals weighing many tons have been found many times. Can be confused with colorless gems as well as glass. Used for creating costume jewelry, delicate bowls, gift items and also to imitate diamonds.

 

Smoky Quartz

Brown or smoky grey colored stone, caused by gamma rays. Found in Madagascar, brazil, Russia, Scotland, Switzerland, and usually confused with tourmaline.

 

Amethyst

Highly valued stone in quartz group, available in purple, violet, and transparent colors. Heat treatment of amethyst produces different colored varieties. Found in US, Madagascar, India, Mexico, Burma, Namibia, Russia and SriLanka.

 

Rose Quartz

Pink in color, due to presence of titanium, can be confused with topaz.

 

Quartz Cat's Eye

Quartz cat's eye is a variety of quartz in which numerous fiber-like inclusions of rutile create chatoyancy effect (like a cat's eye). Can be confused with Chrysoberyl cat's eye, but the name cat's eye (with out the word quartz) referred only for Chrysoberyl cat's eye. Found in SriLanka, brazil and India.

 

Blue Quartz

This is coarse grained blue colored quartz, the inclusions of crocidolite fibres causes this color. Deposits found in Australia, Scandinavia, south Africa, and Virginia; can be confused for lapis lazuli.

 

Dendritic Agate

It is colorless or whitish grey. Found in Brazil, United states and India. Also called Mocha stone because the Indian stones earlier came via the Arabian harbor of Mocha.

 

Sard

Red brown to brown variety of chalcedony. No strict separation from carnelian (darker and browner stones are usually called sard).

 

Chrysoprase

Green color variety of quartz and most valuable stone in chalcedony group. The color is due to presence of nickel in the stone. Color can fade due to sun light or when heated. Found in Zimbabwe, Tanzania, and California.

 

Tiger's eye

Gold yellow or gold brown colored quartz, the chatoyancy effect (Tiger's eye) created due to oxidized iron from decomposed crocidolite to a brown color, keeping the fibrous structure.

 

Aventurine

Green colored quartz and some time with metallic glittery appearance caused by green mica. Can be confused with emerald sometimes.

 

Agate

Found in all colors, deposits are found as ball or almond shaped nodules with sizes ranging from a fraction of an inch to an circumference of several yards.

 

Carnelian

Carnelian is probably named after the color of the kornel cherry because of its color. It is brownish red to orange in color due to presence of iron. The color can be enhanced by heating; found in brazil, India and Uruguay.

 

Chalcedony

Bluish, white grey variety of quartz. Chalcedony also used as species name for all cryptocrystalline quartzes. Chalcedonies in natural state is waxy or dull. Used for cameos, arts, crafts and also in jewelry.

 

Jasper

Found in all color, mostly with striped or spotted. The name itself derived from Greek word which means spotted. Also it found along with agate or opal.

 

Bloodstone

Bloodstone is an opaque, dark green chalcedony with red spots and also called as heliotrope (in Greek 'sun turner'). Presence of chlorite causes green color and red spots are caused by iron oxide.

 

Onyx

Onyx means finger nail in Greek and the name onyx is some time used for uncolored chalcedony (black onyx), other wise it is the name used for layered stones and onyx marble.