Birthstone Month:
Tourmaline is one of the two gemstones associated with the month of October.

Zodiac:
Being one of the two accepted birthstones for the month of October, Tourmaline is one of the zodiac gemstones for Libra and Scorpio.

Chemical Symbol:
The general symbol for Tourmaline is (Na, Ca)(Li, Mg, Al)(Al, Fe, Mn)6(BO3)3(Si6O18)(OH)4

Chemical Make-up:
Tourmaline is made up of the complex Aluminum Borosilicate element, and depending upon the color of the gemstone, one or more of a number of metal ions, usually Iron, Magnesium and Lithium. Chrome tourmaline owes its color to traces of Chromium and Vanadium.

History & Lore:
The name Tourmaline is widely accepted as being derived from the Singhalese expression tura mali, which when translated means “stone of many or mixed colors”.

Tourmaline is often referred to as the rainbow gemstone, due to the huge amount of colors that it is available in. This was certainly believed by the ancient Egyptians who believed that when Tourmaline traveled from its home in the earth's core to the surface, it did so along a rainbow, which subsequently gifted the gemstone with all of the colors of the rainbow.

Tourmalines exhibit piezoelectricity and when these stones become warm they become electrically charged – positively at one end and negatively at the other, acting like a magnet and strong enough to attract small particles of dust or ash. It is for this reason that the Dutch of old used Tourmalines to clean their pipes!

Availability:
Chrome Tourmaline is considered the most valuable of green Tourmalines and is respectively quite rare. Expect to pay high premiums for top quality specimens.

Sources:
Chrome Tourmaline is somewhat of a new addition to the vast Tourmaline family. It was first sourced in Tanzania in the 1960's where deposits continue to be mined to this day. There are also known deposits of Chrome Tourmaline in Kenya, Namibia, and Zambia.

Evaluation:
Tourmaline (regardless of variety) is rated at 7 – 7.5 on the Moh's Scale of Hardness and as such is suitable for all jewelry uses and is considered durable enough to be worn everyday.

Chrome Tourmaline exhibits an outstanding, bright green color that resembles and can even rival that of fine Emerald, which also owes it's amazing color to traces of Chromium. If you are in the market for a Large sized gemstone, Chrome Tourmaline would not be recommended as large specimens are generally much too dark and can contain numerous visible inclusions.

Chrome Tourmaline is also strongly pleochroic. What this means is when viewing the stone from different angels, different color intensities will be visible, with the deepest coloration always being displayed along the stone's main axis. Chrome Tourmalines pleochroic nature, combined with it's durability, clarity and breathtaking color amounts to a truly memorable gemstone that can be past down from generation to generation.

Common Cuts:
Owing to the fact that Tourmaline crystals are long and narrow in shape Tourmaline gems are most commonly, although not exclusively cut into square or rectangular stepped shapes.

Routine Enhancements:
Chrome Tourmalines are occasionally heat-treated in order to lighten colors and to remove “silk” (a form of natural imperfection / inclusion).

Care & Cleaning:
Use warm, soapy water and a soft brush to clean Tourmaline. Ultrasonic cleaners are generally safe. Never use chemicals such as hydrofluoric acid or ammonium fluoride to clean Tourmaline because it can erode the stone. Much like many gemstones, Tourmaline should be kept away from prolonged exposure to extremes of heat and light as this can cause permanent color change. Always keep your Chrome Tourmaline jewelry in a fabric-lined box, away from other jewelry, in order to avoid damage/scratching.