Tourmaline -
December Birthstone (Alternate)
Tourmaline is a large
family of Gemstones with more than 100 hues available. Its name
comes from the Sinhalese turmali, meaning mixed Gemstones due to the
tendency to confuse Tourmalines with other Gems).Tourmaline was first
introduced to the Europeans in the late 1600's or early 1700's by Dutch
traders.For centuries Tourmaline adorned the jewels of royalty. The
Empress Dowager Tz'u Hsi, the last empress of China, valued the rich
pink colors of the Tourmaline type above all other
gemstones.
Tourmaline is generally
thought of as green, but can be almost any colour, indeed some
tourmalines display two or more colours within the same
crystal.Tourmaline exists in more colours than any other gemstone. The
most common colour is a dark green, but bright green chrome tourmalines
are seen, as are blue, red, pink, orange, yellow, colourless, brown,
violet and black. Strongly coloured pink tourmaline is sometimes called
rubellite.
Sources for
this gemstone
Brazil, Afghanistan,Tanzania
and the United States.
Treatments
The Green and Blue colors are
generally very clean. The vivid colors like Bubble Gum Pink in
Tourmaline is HEAT or Cobalt Irradiation treated to enhance and
stabilize the color.
Care
Tourmaline is a very good
choice for jewelry but it should be stored in a separate compartment or
in a jewelry bag to prevent scratching by harder Gemstones.
Jewelry featuring Tourmaline should not be cleaned in an
ultrasonic or steam cleaner. We recommend ionic cleaners and/or
warm, soapy water and a soft brush as the best way to clean
Tourmaline.
Technical
Information
| Chemical Composition
and Name |
- Complex
Aluminium Borosilicate |
| Hardness |
7.0 to
7.5 |
| Refractive
Index |
1.616 - 1.634 to
1.630 - 1.652 |
| Bi-refringence |
0.014 to
0.021 |
| Other Optical
Properties |
Uniaxial |
| Optic Sign |
Negative |
| Specific
Gravity |
3.02 -
3.26 |
| Crystalline
System |
Trigonal |
