Andalusite is named after Andalusia, the province of Spain where it was first discovered. Andalusite is a strongly pleiochroic gem that shows different colors when viewed from different directions. While it is a strikingly beautiful gem, it is largely unknown by the gem buying public. With a hardness of 7.5 on the Mohs scale, it is very suitable for all kinds of jewelry.
Andalusite colors
Buying Andalusite
Where is Andalusite found?
Common Andalusite Treatments
World-famous Andalusite
Andalusite gemology
Andalusite legends & lore
Andalusite colors
Andalusite is pleochroic, which means it display different colors when viewed from different directions. When cutting many pleochroic gemstones, such as iolite and tanzanite, the trick is to minimize the pleochroism and to maximize the single best color. Andalusite requests the opposite: cutters try to orient the gem to get a pleasing mix of colors, like orangey brown and a yellowish green or gold.
Buying Andalusite
Color
The colors of andalusite cover the range of yellow-green, green, brownish red and reddish brown. Depending on the cut each gemstone carries two colors that also differ in intensity, or blend into a mosaic.
Lighting
The attraction of andalusite comes from its play of colors if one changes the viewing angle. A similar effect is gained when the light comes from different directions.
Clarity
Transparent andalusite of gemstone quality is rare. Dark inclusions produce cruciform shapes in a variety called chiastolite.
Cut
The andalusite nature, which shows shades of brown, green and reddish brown depending on the orientation of the crystal, can be enhanced by specific orientation and cut. Those cuts with a long axis such as an oval, marquis or emerald cut tend to show one color near the center and a second, usually darker color near the ends. Square and round cuts usually blend the colors into a mosaic.
Andalusite location and deposits
Deposits are found in Australia, Brazil, Canada, Russia, Spain (Andalusia), Sri Lanka and the United States.
Common Andalusite treatments
There are no known treatments to enhance Andalusite.
World-famous Andalusite
As a lesser-known gemstone, andalusite hasn't gained fame as of yet.
Andalusite gemology
Species: Andalusite
Color: Yellow-green, green, brownish-red, reddish brown
Chemical composition: AI2,SiO5, aluminum silicate
Crystal system: (Orthorhombic), thick columnar
Hardness: 7.5 (Mohs scale)
Specific gravity: 3.05 - 3.20
Refractive index: 1.627 - 1.649
Birefringence: -0.007 to -0.013
Optical character:
Color of streak: White
Absorption spectrum: 553, 550, 547, 525, 518, 495, 455, 447, 436
Fluorescence: Weak; green, yellow green
The Andalusite zodiac, myth & legend
As a lesser-known gemstone, andalusite produces a blank page in the books of myth, history, wisdom, the zodiac scheme or the relation between planets and mankind. |
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