The gemstone Tourmaline is an official October birthstone. Tourmalines are precious stones displaying a unique splendor of colors. According to an ancient Egyptian legend this is the result of the fact that on the long way from the Earth's heart up towards the sun, Tourmaline travelled along a rainbow. And on its way it collected all the colors of the rainbow. This is why nowadays it is called the "Rainbow gemstone". Tourmaline is 7 - 7.5 on the Mohs scale of hardness. Tourmalines are mined everywhere in the world. There are important occurrences in Brazil, in Sri Lanka and South and Southwest Africa. Other occurrences are situated in Nigeria, Zimbabwe, Kenya, Tanzania, Mozambique and Madagascar, Pakistan and Afghanistan. Tourmalines are also found in the USA, in Maine and Utah. But although there are rich occurrences of Tourmalines all over the world, good qualities and fine colors are only rarely offered on the market. Therefore, then, the price range achieved by Tourmaline almost matches its wide range of colors. Click here for a picture in natural form. Click here for more faceted and natural specimens.

Description:

Tourmaline has a special place in the hearts of mineral collectors as well as in that of gem and gemstone enthusiasts. Its nearly universal popularity is based upon two very important facts: It is a bright and beautiful gemstone that can be found in just about any color; Materials that are of acceptable quality are affordable to most purchasers. The word "rainbow" is used figuratively to describe Tourmaline. In reality, it is a well recognized fact that tourmaline's diversity in color is not limited to the seven colors of the rainbow. Tourmaline can be colorless to just about any color, hue, or tone known to man. And if range of colors among different Tourmalines is not enough, individual crystals can vary in color along their length or in cross-section. The variations in color along a crystal's length give rise to the bicolor and tricolor Tourmalines which have multitudes of color combinations.

Chemistry:

The Tourmaline Group has a general formula of AX₃Y₆(BO₃)₃Si₆O₁₈(O, OH, F)₄. The A can be either calcium or sodium. The X can be either aluminum, iron, lithium or magnesium. The Y is usually aluminum, but can also be chromium or iron. Some potassium can be in the A position, some manganese can be in the X position and some vanadium can be found in the Y position, but these elements are usually not represented in the formulas of the tourmaline members. There are many unique properties of Tourmalines. First, they are piezoelectric which means that when a crystal is heated or compressed (or vibrated) a different electrical charge will form at opposite ends of the crystal (an electrical potential). Conversely if an electrical potential is applied to the crystal, it will vibrate. Secondly they are pleochroic which means that the crystal will look darker in color when viewed down the long axis of the crystal than when viewed from the side. This property goes beyond the idea that the crystal is just thicker in that direction. Even equally dimensioned crystals will demonstrate this trait. This property can be used as an advantage by gem cutters who may wish to enhance a crystal's pale color or weaken a strongly colored crystal. The four most common and well known Tourmalines are distinguished by their color and transparencies. Elbaite is the gemstone Tourmaline and comes in many varied and beautiful colors. It is transparent to translucent and is highly prized as minerals specimens and as gemstones. Elbaite is easily the most colorful of all the gemstones. The iron rich schorl is the most abundant Tourmaline and is black and opaque. It is a common accessory mineral in igneous and metamorphic rocks and can form nice crystals. Although too opaque to be used as a gemstone, schorl is used as an ornamental stone when found as inclusions in quartz, a stone is called "tourmalinated quartz". Usually when someone refers to Tourmaline they are referring to either elbaite or schorl. The two other more common Tourmalines; dravite and uvite are much less common than elbaite or schorl, but they are getting noticed for their beautiful specimens. Some of dravite's crystals are nicely formed, translucent brown and they can reach a rather large size. Uvite is a green translucent to opaque Tourmaline that is growing in popularity and is being cut as a gemstone.

These are the members of the Tourmaline Group of minerals:

• Buergerite (Sodium Iron Aluminum Boro-silicate Hydroxide Fluoride)
• Chromdravite (Sodium Magnesium Chromium Iron Aluminum Boro-silicate Hydroxide Fluoride)
• Dravite (Sodium Magnesium Aluminum Boro-silicate Hydroxide)
• Elbaite (Sodium Lithium Aluminum Boro-silicate Hydroxide)
• Feruvite (Calcium Iron Magnesium Aluminum Boro-silicate Hydroxide)
• Foitite (Iron Aluminum Boro-silicate Hydroxide)
• Liddicoatite (Sodium Lithium Aluminum Boro-silicate Oxide Hydroxidem Fluoride)
• Olenite (Sodium Aluminum Boro-silicate Oxide Hydroxide)
• Povondravite (Sodium Iron Boro-silicate Hydroxide Oxide)
• Schorl (Sodium Iron Aluminum Boro-silicate Hydroxide)
• Uvite (Calcium Sodium Magnesium Iron Aluminum Boro-silicate Hydroxide Fluoride)

Legends, Myths and Healing Properties:

No Tourmaline exactly resembles another one: this gemstone shows many faces and is thus excellently suited to match all moods and tempers. It does not come as a surprise, then, that ever since ancient days it has been attributed with magical powers. Tourmaline is supposed to be an especially powerful influence on love and friendship, lending them permanence and stability.