Amethyst, the most precious member of the quartz family, exhibits purple shades ranging from pale lilac to deep purple, sometimes exhibiting reddish or rose overtones. Very deep-colored amethysts are the finest and most highly valued. Some stones are so over-saturated with color they have areas that are blacked out, which can negatively impact their value. Paler shades, sometimes called "Rose of France," were common in Victorian jewelry. Banding—darker and lighter zones of color—is also a common occurrence. Occasionally, amethyst is even found combined with its sister quartz, citrine, into a single stone called ametrine.

The birthstone for February, amethyst is an extremely popular gem for jewelry because of its regal color, variety of sizes and shapes, affordability and wide range of hues. It also is the recommended gem for couples celebrating their 6th and 17th wedding anniversaries. With a hardness of 7.0 on the Mohs Scale , amethyst can occur as long prismatic crystals that have six-sided pyramids at either end, or can form as drusies that are crystalline crusts that only show the pointed terminations.

The ancient Greeks believed that amethyst made one immune to the effects of alcohol. In fact, the name even comes from the Greek word amethystos, which means “not drunken.” Legend has it that the amethyst originated from Bacchus, the god of wine. Bacchus became angry at the mortals and vowed that the next mortal to cross his path would be eaten by tigers. Amethyst, a beautiful young maiden, was on her way to worship the goddess, Diana. Diana turned her into colorless quartz to keep her from being eaten. Bacchus observed the miracle and repented his hasty decision. He poured wine over the young maiden, leaving her feet and legs colorless. This is the reason that amethyst crystals are usually uneven in color and have a colorless base at the bottom. Because amethyst was believed to prevent drunkenness, wine goblets were often carved from it in ancient Greece. Today, the gem still symbolizes sobriety.

Amethyst has been a part of history throughout the ages. Evidence suggests that prehistoric humans used amethysts for decoration as early as 25,000 B.C. Legends suggest that the Egyptian queen Cleopatra wore an amethyst signet ring, as did Saint Valentine, who bared an amethyst engraved with the figure of Cupid. During medieval times, people used the stone as medication to stay awake and alert. Leonardo Da Vinci claimed that amethyst could dissipate evil thoughts and quicken the intelligence. In some legends, the stone represents piety, celibacy and dignity. In the Middle Ages, for instance, the gem was an important ornamentation for the Catholic Church and other religions. It was considered the stone of bishops, and they still often wear amethyst rings. In Tibet, amethyst is considered sacred to Buddha and rosaries are often made from it. Amethyst has also long been a favorite of kings and queens for its royal purple hues that symbolize wisdom, strength and confidence. Amethysts are even featured in the British Crown Jewels and were worn by Catherine the Great.

Amethyst’s availability and magical qualities make it the stone of preference in ancient lore and mysticism. As a meditation stone, it is said to quiet the mind, promote contemplation, sharpen psychic powers and uplift the spirit. It is a stone of deep wisdom. Folklore says it can quicken the wit, calm fears, ward off anger and overcome alcoholism. It has a royal purple essence that is said to lend courage to travelers, scare off thieves and protect travelers from harm, sickness and danger. Placed under the pillow or worn to bed, there are claims it promotes peaceful sleep, pleasant dreams, and the healing of tired joints and muscles. Amethyst can also be worn to supposedly make the wearer gentle, amiable and happy.

The stone is mined in Brazil, Uruguay, Bolivia and Argentina, as well as in Zambia, Namibia and other African nations. Very dark amethyst in small sizes also is mined in Australia. But the ideal for fine quality amethyst was set by a Siberian variety, often called Russian or Uralian amethyst, which is now considered a defunct source. Generally, South American amethyst tends to come in larger sizes than African amethyst, but the African variety has a reputation for having deeper color intensity and is therefore considered more valuable. The African version also is harder to come by than amethyst mined from South America. Most of today's amethyst comes out of Brazil.

Marcasite, a name derived from the Arabic word for pyrite, is the term applied to small polished and faceted stones inlayed in sterling silver. Their color is usually described is being pale bronze, looking rather gray with a greenish tint. A multi-colored tarnish may exist as a result of oxidation. With a metallic luster and opaque crystals, marcasite ranks 6.0-6.5 on the Mohs Scale. Occurrences are worldwide, especially in the United States, Mexico, France, Peru, China and Russia.