October has two birthstones the pink tourmaline and the opal. Both of these stones come in a wide range of colors.
Tourmaline is available in a wide variety of colors from black to bluish-black, dark brown, yellow, medium brown, blue to neon blue, lime to dark forrest green, red and reddish purple, yellow, pink, and colourless.
The gemstone Tourmaline is the official birthstone for October as adopted by the American National Association of Jewelers in 1912. It also the tradidional birthstone for October, the stone for the Zodiac sign of Leo, and the accepted gem for the 8th wedding anniversary.
The water content is usually between three and ten percent, but can be as high as twenty percent. Opal ranges from clear through white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Of these hues, the reds against black are the most rare, whereas white and greens are the most common. These color variations are a function of growth size into the red and infrared wavelengths. Opal is Australia's national gemstone.
