Andalusite
A variety of Minerals
What is Andalusite?
You might not know andalusite by name, but if you have porcelain spark plugs in your vehicle, you experience the rugged nature of andalusite every time you start your engine! It is incredibly strong and can withstand extreme heat and pressure without any signs of stress. Gem-quality stones are rare, but display fascinating color-changing effects.
Uses & Applications
Andalusite is primarily used in refractories, kilns, incinerators, and other industrial processes. This mineral is also used to make high-temperature ceramics used in furnaces and porcelain used in spark plugs. High-quality specimens are used as gemstones for jewelry or mineral collections.
Healing Properties
Andalusite is considered a protection stone that is believed to ward off negative energy and the evil eye. Its positive energy helps to remove emotional blockages, allowing for self-realization and self-acceptance, which encourages a more complete healing and personal growth for the mind, body and spirit. To encourage better sleep, place one on a table near the bed. A small piece can be carried for protection throughout the day.
Optical Properties
- Refractive Index
- 1.627-1.650
- Birefringence
- 0.007-0.013
- Pleochroism
- Orange/brown stones - strong trichroism: yellow, olive green, reddish brown; Yellow stones - strong: yellow, olive-green, red-brown; Green stones - strong: yellow, olive green, red-brown
- Optical Character
- Biaxial negative
- Dispersion
- 0.016
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Andalusite Localities Map
See where Andalusite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
The Meaning
Andalusite is a gemstone with a rich history, supposedly worn as an amulet and used during healing rituals amongst ancient civilizations. The folklore is somewhat conflicting, with some cultures believing that fighters were typically drawn to the stone and others holding the opinion that andalusite transformed a fighter into a peacemaker when worn.
Associated Chakras
Key Characteristics
Rock Types of Andalusite
The variety chiastolite commonly contains dark inclusions of carbon or clay which form a cruciform pattern when shown in cross-section. This stone was known at least from the sixteenth century, being taken to many European countries, as a souvenir, by pilgrims returning from Santiago de Compostela. A clear variety found in Brazil and Sri-Lanka can be cut into a gemstone. Faceted andalusite stones give a play of red, green, and yellow colors that resembles a muted form of iridescence, although the colors are actually the result of unusually strong pleochroism.
Formation of Andalusite
Andalusite is a common metamorphic mineral which forms under low pressure and low to high temperatures. The minerals kyanite and sillimanite are polymorphs of andalusite, each occurring under different temperature-pressure regimes and are therefore rarely found together in the same rock. Because of this the three minerals are a useful tool to help identify the pressure-temperature paths of the host rock in which they are found. It is particularly associated with mica schist.
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Quick Facts
Physical Properties
- Color
- Pink to red brown, occasionally yellow, green, white, gray rarely violet
- Hardness (Mohs)
- 6.5 - 7.5
- Density
- 3.149 g/cm³
- Streak
- White
- Luster
- Greasy, Vitreous, Sub-vitreous
- Crystal System
- Orthorhombic
Chemical Properties
- Chemical Formula
- Al2(SiO4)O
- Elements
- Al, O, Si
Also Known As
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