Properties of Andalusite

Andalusite is a mineral that belongs to the aluminum silicate group. It is known for its distinctive and often striking crystal shapes, which can include prisms and cross-shaped forms. The mineral is typically found in metamorphic rocks and is associated with regions that have undergone high-pressure, high-temperature conditions during their geological history.

Image of andalusite mineral
Credit: Jan Helebrant, CC BY-SA 2.0, via Wikimedia Commons

The following table provides a comprehensive list of andalusite properties in both SI and US customary/Imperial units at normal temperature and pressure (NTP).

Note: click on the icon to switch between Metric and Imperial units.

Table of Andalusite Properties
Physical Properties
Metric
Chemical FormulaAl2SiO5
Molar Mass162.04 g/mol
Crystal SystemOrthorhombic
Mohs Hardness6.5 - 7.5
Density3130 - 3160 kg/m3
ColorUsually pink, white, rose, dark green, gray, brown, red, or green or with clouded inclusions
DiaphaneityTransparent to translucent
LusterVitreous (glassy)
Cleavage(110) distinct, (100) indistinct, (010) poor
FractureUneven, splintery, brittle
StreakWhite

Note: unless stated otherwise, all values are taken at room temperature (approximately 20°C or 68°F) and 1 atm pressure. (1 atm = 101,325 Pa)

Related Pages
References: 1) Cardarelli, François. Materials Handbook: A Concise Desktop Reference. Switzerland: Springer International Publishing, 2018. 2) CRC Handbook of Chemistry and Physics, 97th Edition. United Kingdom: CRC Press, 2016-2017.