andalusite

Name:

andalusite

A photo of the mineral andalusite

Class:

Silicates

Chemistry:

Al2SiO5 Aluminum Silicate

Color(s):

red, brown, tan, olive green

Hardness:

6.5 - 7.5

SpecGrav:

3.13 - 3.16

Fracture:

uneven

Cleavage:

perfect

Crystal:

Orthorhombic, often square in cross section with a distinguishing X in cross section

Envronment:

low pressure metamorphic rocks low in Ca and rich in Al.

Association:

kyanite, sillimanite, cordierite, and corundum

Locals:

| Calif., Penn., Mass. Maine, USA | Brazil | China | Spain | Italy | Australia |

Misc:

The variety with the strong X-pattern is called "chiastolite", from the Greek "chiastos", meaning "X-marked". The name, Andalusite, comes from the Spanish local Andalusia. It is one of three polymorphs of Aluminum Silicate, the other two being Sillimanite, and Kyanite. They are related through their pressure and temperature of formation.

Photos
& Locals:

1.) China
2.) China (closeup)

3.) China

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Name:	andalusite
Class:	Silicates
Chemistry:	Al2SiO5 Aluminum Silicate
Color(s):	red, brown, tan, olive green
Hardness:	6.5 - 7.5	SpecGrav:	3.13 - 3.16
Fracture:	uneven	Cleavage:	perfect
Crystal:	Orthorhombic, often square in cross section with a distinguishing X in cross section
Envronment:	low pressure metamorphic rocks low in Ca and rich in Al.
Association:	kyanite, sillimanite, cordierite, and corundum
Locals:	\| Calif., Penn., Mass. Maine, USA \| Brazil \| China \| Spain \| Italy \| Australia \|
Misc:	The variety with the strong X-pattern is called "chiastolite", from the Greek "chiastos", meaning "X-marked". The name, Andalusite, comes from the Spanish local Andalusia. It is one of three polymorphs of Aluminum Silicate, the other two being Sillimanite, and Kyanite. They are related through their pressure and temperature of formation.

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