Amethyst is a purple to light crimson gemstone of the quartz family. Its name derives from the Greek amethystos meaning "not drunk." Indeed, it was regarded as a talisman against intoxication during Antiquity. The coloring of the amethyst is due to the presence of iron and high irradiation. Amethyst darkens slightly and gradually in the presence of artificial light, and some can fade in the daylight. The main countries where amethyst is found are Brazil, Madagascar, Mexico, Canada, the United States, Sri Lanka, Zambia, Myanmar, Uruguay, India, Namibia and Russia. A little bit of history: In Classical (Greco-Roman) mythology, Amethyst was a young nymph who was transformed into a crystal by the goddess Diane, in order to protect her from Bacchus, the god of wine. Furious, the god is said to have poured his cup of wine on the crystal, giving it its color. The notion that amethyst prevents drunkenness comes from this legend.

The western birthstone chart is based on the biblical description of the breastplate of the high priest Aaron (brother of Moses) that consists of 12 stones that represent the 12 tribes of Israel. Across cultures and time, powers of protection were conferred to those who wore them. In 1912, the American national association of jewelers established a modern birthstone chart.

Month	Stones
January	Garnet
February	Amethyst
March	Aquamarine
April	Diamond
May	Emerald
June	Pearl or Alexandrite
July	Ruby
August	Peridot
September	Sapphire
October	Opal or Tourmaline
November	Citrine
December	Blue Topaz

Citrine is a glassy yellow to brown colored gemstone of the quartz family. It actually is a silicon dioxide (silica). Its yellowish color is due to the presence of a very small amount of iron oxides in the mineral. Its name is derived from the lemon of which she shares the yellowish shade. Natural citrines are rare. Most of them originate from Brazil, the United States, Madagascar, Argentina, Myanmar, Scotland, Spain, Namibia and Russia.

They used to be known as semi-precious stone, however, this appellation was revoked because it was considered pejorative. Gemstones (also fine gem or gem) are translucent or transparent (topaz, quartz, opal, etc.). The following stones are classified as gems: amber, aquamarine, amethyst, citrine, rock crystal, cordierite, garnet, peridot, tanzanite, topaz, tourmaline and zircon. There are also ornamental stones such as lapis lazuli and turquoise, which are often mistaken as gemstones. This term generally designates opaque colored stones or stones of a lesser value. The reconstituted stones are manufactured by a process that reduces useless stones to a powder, the powder is then mixed with glue. Thus making a complete stone. Dyes can be added to give a certain uniformity to the stone's appearance. The term stabilized means that a natural stone, such as turquoise, was too porous and has been dipped in a resin bath, or into another protective lacquer, to solidify. In France, the only stones said to be precious are diamonds, sapphires, emeralds and rubies. Around the world, this term refers to any gem of great value.

The term "quartz" refers to a family of minerals within the group of silicates. Quartz composes 12% of the lithosphere (outermost shell) and is the most common mineral. Quartzs are divided into different categories, among them the macrocrystalline quartz (amethyst, citrine, rock crystal, quartz smoke, rose quartz, blue quartz, quartz cat-eye, iron-eye, falcon-eye and tiger-eye ) and microcrystalline quartz (chalcedony, carnelian, onyx, agate, chrysoprase, jasper and petrified wood).

During Antiquity as well as Middle-Ages, it was believed that the formation of gems was influenced by constellations, some gems were as bright as stars. They were thought to be the mirrors of the cosmos. Therefore each planet was associated with one or more gems that possess “magical” properties. These beliefs still circulate in todays modern society, even though there are no tangible proof to support them.

Sign	Stones
ARIES	Carnelian, red jasper
TAURUS	Carnelian, pink quartz
GEMINI	Citrine, tiger's eye
CANCER	Chrysoprase, aventurine
LEO	Rock crystal, golden quartz
VIRGO	Citrine, yellow agate
LIBRA	Orange citrine, smoked quartz
SCORPIO	Blood red Carnelian
SAGITTARIUS	Sapphire, chalcedony
CAPRICORN	Onyx, rutilated quartz
AQUARIUS	Turquoise, falcon eye
PISCES	Amethyst, quartz amethyst