History and General Information about Natural Andalusite Gemstone
Andalusite gemstone, an exquisite pleochroic stone, was first discovered in the Andalusia region of Spain, and takes its name from this region. Andalusite is used widely in making jewelry and objets d’arts, on account of its hard texture and durability. It is often regarded as a poor cousin to the extremely valuable though rare Alexanderite gemstone, since it mimics the stone in color play, showing a range of earth tones. It is a very popular gem in jewelry, especially for men.
Chemical Compsition of Natural Andalusite Gemstone
The chemical formula of Andalusite Gemstone is Al2SiO5 and it is called Aluminium silicate, having a hardness of 7.5 on the Mohs scale. Found mainly in metamorphic rocks, as a variety of mineral aluminium silicate, the andalusite is a polymorphic stone, often confused with fibrolite and kyanite, since they all have the same chemical quality but different crystal structure.
Physical Properties of Andalusite Gemstone
Andalusite has an orthorhombic crystal structure, with a vitreous quality which makes the stone seem transparent as well as translucent.
Andalusite, being a pleochroic stone, that is, showing different colors in different directions, according to the way in which it is cut and polished, can take on a variety of colors, which is what makes it unique. It occurs in colors such as green, brown, yellow, red, brownish green and greenish brown, depending upon the colour of the rough and the way in which it has been cut.
Andalusite can be cut and shaped in many different ways, but on account of its pleochroism, the stone gives out its best colors in rectangle cushion shapes, or ovals, as the normal round cut usually makes the colors come together, robbing the stone of its distinctive colors.
A very unique quality of this stone is that, unlike most stones, which are cut in a way so as to reduce the pleochroism, and allow for a single tint to be prominent, the facets of the andalusite are oriented in such a way that the stone reflects a fusion of colors.
Stones in the range of five carats are easily available, while three carats and less can be found in plenty, but stones weighing above 10 carats are hard to come by.
Andalusite displays inclusions and most of them contain white rutile needles, but the ones where the carbon inclusions are placed in the form of a cross are valued as religious objects.
Price of natural Andalusite gemstone
The price of the stone depends upon its size, and thus a commercial quality stone, below five carats can be easily bought for about $10-$25 per carat, but larger well cut, customized stones can cost anywhere upwards of $50 per carat.
Producers of Andalusite Gemstone
Although this aluminium silicate mineral is found in large quantities in Kazakhstan, South Africa and the Inyo Mountains of USA, the gem is yielded mainly in the deposits found in Sri Lanka and the Minas Gerais, Brazil, and in regions of Spain and France.
Simulants of Andalusite Gemstone
Andalusite is often confused not only with Alexanderite, but also being dimorphous, that is, having the same chemical composition as fibrolite and kyanite, it is confused with these gemstones too.
Trivia and other interesting information on Andalusite gemstone
In alternative therapy, using gemstones, andalusite is used to treat diseases ranging from AIDS to improving memory. It is identified with the heart charkas, of the Hindu tradition, and with the solar plexus. Therapists use it to calm people, as well as in meditation and also to improve and aid memory.
Chiastolite, also known as star Andalusite, is an impure variety, but is widely used as an amulet, since it contains inclusions, placed in such a way that they look like a cross, and this is the asterism, another quality found in gemstones, displayed by the versatile Andalusite.
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