Exploring Varieties: An Overview of Different Tourmaline Gemstones
Tourmalines, renowned for their vibrant and diverse colours, have long been a favourite among jewelers and collectors. This mineral group, defined by its unique chemistry and atomic structure, includes over a dozen species, but only a few contribute significantly to gem-quality stones.
One of the most intriguing varieties is the Paraiba tourmaline, vividly coloured blue to green stones that captured the imagination of buyers since their discovery in about 1989. Another fascinating species is lithicoatite, defined by the substitution of lithium for some magnesium, which may be of any colour and is often spectacularly colour-zoned.
Colour zoning, a common feature of tourmalines, can be seen in some crystals that are zoned concentrically from their centres to their surfaces. This zoning is responsible for the intriguing phenomenon where thin stones look green when light is shone through them; as thickness increases, they appear progressively more orange and then red.
Any combination of colours is possible in parti-coloured tourmalines, with most stones being pink and green, or pink, white, and green. The colour change in tourmalines depends mainly on the thickness of the stone, with about 15mm being enough to cause many stones to appear red.
Some chrome tourmalines display a colour change, with red being seen more easily in incandescent light and green in daylight. This colour change effect, known as chatoyancy, is also responsible for the cat's-eye effect seen in some tourmalines, caused by reflection from numerous parallel long and thin inclusions.
Tourmalines containing sodium are of significant interest, with Elbaite being the most common gem tourmaline and supplying most gem tourmalines. Substitution of calcium for sodium produces uvite, while Elbaite contains lithium as an additional element.
Indicolite is used for blue and some greenish blue tourmalines, while rubellite is red, and verdelite is used for green stones that are coloured by iron. Chrome tourmaline is green, with chromium and/or vanadium causing the colour. Stones coloured by iron do not look pink to red through the Chelsea color filter.
Schorl is black and opaque when large enough to be fashioned and contains iron as an additional element. Indicolite, rubellite, and verdelite are just a few examples of the many coloured varieties of tourmaline, each with its unique charm and allure.
Whether it's the vibrant blues of indicolite, the fiery reds of rubellite, or the mesmerising colour change of chrome tourmaline, the world of tourmalines offers a kaleidoscope of colours that continue to captivate and inspire.
- In the realm of fashion-and-beauty, the mesmerizing color change of chrome tourmaline often catches the attention, creating a stunning effect reminiscent of a cat's-eye.
- If one is revamping their home-and-garden decor, the black and opaque Schorl tourmaline with its added iron content can serve as an eye-catching centerpiece.
- For travel enthusiasts, a visit to the Colombia's Muzo mine might be intriguing, as it is the source of Elbaite, the gem tourmaline with lithium and sodium that provides a diverse spectrum of colours in the lifestyle sector, from the vibrant blues of indicolite to the fiery reds of rubellite.
