A member of the zoisite family of minerals, tanzanite is found only in shades of blue or purple, the most popular being a violet-blue. While tanzanite is typically heat treated to enhance its blue color, it is naturally trichroic, meaning that it displays three different colors (blue, purple and bronze) when viewed from different angles. Tanzanite exhibits a hardness of 6.5-7 on the Mohs scale. It gets its name from the country of Tanzania, the only place in the world where it is found. Tanzanite was discovered as recently as 1967, and was christened by colored stone experts to be "the gemstone of the 20th century." Owing to its fast growing popularity, the American Gem Trade Association added it as an alternative December birthstone in the United States in 2002.
Topaz is one of the most common gemstones worldwide. It has a very good hardness of 8 on the Mohs scale. Topaz comes in a rainbow of colors, the most valuable of which are the red, pink and orange stones which are mined in Brazil, Pakistan and Russia. Colorless topaz is mined in Sri Lanka, Nigeria and China. Blue topaz is colorless in its rough form, and takes on its blue hue only after exposure to irradiation enhancement. It is quite sensitive to heat and sunlight, and may lose all of its color when exposed to strong UV rays for extended periods of time. Many cultures have claimed that topaz has mythical and magical strengthening powers. It is the traditional November birthstone and the alternative December birthstone in the United States.
The word tourmaline was derived from the Sinhalese words 'tura mali', meaning 'mixed colored'. As its name indicates, tourmaline is found in a vast array of colors and color mixtures, more than any other gemstone in the world. For this reason, no two pieces of tourmaline are ever identical. Since many of its colors look similar to the colors of other gemstones, many tourmaline stones have been misidentified as rubies and sapphires. This colorful gem exhibits a good hardness of 7-7.5 on the Mohs scale. The rarest colors, which include copper and electric blue, are the most valuable. Many magical powers have been attributed to tourmaline over the ages, including the power to enhance artistic creativity. Although Brazil is the most common source of tourmaline, the stone is also mined in Tanzania, Madagascar, Australia, Stri Lanka, the United States, and Russia. It is an alternative October birthstone in the United States.
A member of the copper family, turquoise is one of the oldest gemstones known to man, having been treasured by countless ancient civilizations across the globe. It is thought to have originated in Iran, where many Persians wore turquoise on their turbans to protect against the evil eye. Native Americans, Egyptians, Chinese and Tibetans also believe turquoise holds spiritual and protective powers. Turquoise is known for its light blue color, which can range from greenish-blue to sky blue, and at times exhibits yellow, black, gray, or even brown veining. This renowned gemstone exhibits an average hardness of 6 on the Mohs scale. As Iranian sources of turquoise have been nearly depleted over the centuries, the stone is now mined mainly in the southwestern United States, Mexico, Afghanistan, Israel and China. Turquoise is the December birthstone in the United States.