Andalusite is poised to be the next beauty queen on the gem market. This beautiful multi color gems is still surprisingly affordable.  It is being called the poor man's Alexandrite because of the way it can appear to change colors depending on how it is viewed.  25 years ago very few people had ever heard of Tanzanite, now Tanzanite is one of the most popular gems in the world!

Now is the best time to invest in Andalusite before the price starts to climb.

Andalusite is pleochroic, different colors in different directions. When cutting most pleochroic gemstones, such as Iolite and Tanzanite, the trick is to minimize the pleochroism and maximize the single best color. Andalusite is the opposite: cutters try to orient the gem to get a pleasing mix of colors: orangey brown and a yellowish green or gold.

3.5mm Andalusite gems

Andalusite ... Is trichroic in nature. It shows different shades of brown, green and reddish brown, depending on the orientation of the crystal, and the way it is cut. Gem 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, as shown in the gems above.

Andalusite was originally discovered in Andalusia, Spain.

Now Andalusite is mostly mined in Brazil, but it can also be found in Sri Lanka, Russia and the US.

Most specimens of Andalusite contain some inclusions, the most common being rutile needles.

White Quartz with Rutile Needles

Andalusite is very hard and can be used for almost any kind of jewelry . Poorly cut and polished stones can be pretty dull and lifeless, but a large, well cut Andalusite is absolutely STUNNING !!!

10x8mm Green Andalusite showing flashes of red and yellow.

Andalusite is a polymorph with two other minerals; Kyanite and Sillimanite. A polymorph is a mineral that shares the same chemistry but a different crystal structure with another, or other, minerals. A unique variety of andalusite is called "Chiastolite". It contains black or brown clay and/or carbonaceous material inclusions in the crystal. These inclusions are arranged in regular symmetrical shapes. Usually they are in the form of a cross or X.

Star Sillimanite

PHYSICAL CHARACTERISTICS:

• Color is white, red, brown, orange and green
• Luster is vitreous
• Transparency crystals are transparent to translucent.
• Crystal System is Orthorhombic; 2/m2/m2/m
• Crystal Habits include prismatic crystals with a square cross section terminated by a pinacoid, also massive and granular.
• Cleavage is good in two directions
• Fracture is splintery to subconchoidal
• Hardness is 7.5
• Specific Gravity is approximately 3.15+ (above average)
• Streak is white
• Associated Minerals are Cordierite, Biotite, Feldspars, Quartz, Kyanite and Sillimanite.
• Other Characteristics: dark inclusions produce cruciform shapes in the variety Chiastolite.
• Index of refraction is 1.632-1.638.
• Notable Occurrences include Andalusia, Spain; Austria; California, USA and China.
• Best Field Indicators are crystal habit, color, inclusions (if present) and hardness.

Andalusite Rough

CHEMISTRY                  Al2SiO5 + Fe
CRYSTALLOGRAPHY Orthorhombic
REFRACTIVE INDEX  1.629 - 1.650
HARDNESS                    6.5 - 7.5
SPECIFIC GRAVITY    3.13 - 3.17
CLEAVAGE                   Distinct one direction
HEAT SENSITIVE        No
WEARABILITY            Very Good
SPECIAL CARE INSTRUCTIONS      None

ENHANCEMENTS Can be heat treated to improve color. Rarely done.