Hardness 7, Specific gravity 2.65, Refractive index 1.54–1.55

 Quartz comprises a wide assortment of semi-precious gems, and it makes up the largest mineral group. Quartz is silica (oxide of silicon) and appears in two forms, crystalline, which grows in a single crystal, and chalcedony, which is formed by millions of micro-crystals. Quartz is low in dispersion, and has brilliance, fire, and a glassy luster. Clarity is an important factor when judging quality. Quartz is free from cleavage and is durable. When broken, is has a curved fracture. Quartz is mined mainly in Brazil and Uruguay. It is inexpensive. Transparent quartz stones: rock crystal, golden topaz (citrine), amethyst, and smoky quartz. Colorless crystalline quartz is known as rock crystal. This is the kind of crystal that is used in crystal balls. Amethyst is the most popular crystalline quartz to be used in jewelry. Tibetan Buddhists consider amethyst sacred to Buddha, and they often wear amethyst beads. Some chalcedony quartzes: onyx, agate, and jasper. Chatoyant crystalline stones: the greenish-yellow cat’s eye and the golden brown tiger’s eye. Chatoyant crystals are stones that reflect a single streak of light when cut in a cabochon. Quartz is said to help the wearer develop spiritual qualities, and it is therefore of benefit to spiritualists, astrologers, palmists, and philosophers. It is also said to help improve eye, stomach, blood problems, and throat infections. Rock Crystal In Hindi, rock crystal is known as sphatik. This is the common transparent crystal widely recognized. Rock crystal is an inexpensive substitute for diamonds, but is not very effective. If being used as a diamond substitute, be sure to purchase a stone of at least eleven carats. Rock crystal is best set in gold. Wearing rock crystal protects against curses, and helps one to have undisturbed sleep. Crystal necklaces are said to aid concentration. If poison is placed in a cup made of rock crystal, the substance will become smoky. Rock crystal brings good fortune, increases sexual prowess, and protects one from dangerous animals. It is auspicious to wear rock crystal while offering oblations for departed ancestors. Rock crystal is found in Brazil, the United States, Russia, Japan, Hungary, France, and Madagascar. In India, it can be found in Kashmir, the Vindhyachal Mountains, Spiti, Kulu and Satpura in Madhya Pradesh. A fractured or discolored crystal should not be used, as it will cause trouble for the wearer.  If you know of information that is not listed here, or if you would like to help update our listings, please e-mail us at: