Andalusite

Andalusite is a popular gemstone composed of aluminum silicate. ^[1]

Andalusite: Quick Facts and Characteristics

Some quick facts for Andalusite:

• Transparency: Andalusite can be opaque, translucent or transparent.
• Crystallography: In terms of crystallography, andalusite is orthorhombic.
• Luster: In terms of luster, andalusite is vitreous (glassy).
• Streak: Andalusite streaks colorless.
• Hardness: Andalusite's hardness ranges from 6.5 to 7.5 on the Moh's scale.
• Specific Gravity: Andalusite's specific gravity ranges from 3.13 to 3.17.

Andalusite: Background and Summary

Andalusite is a mineral that belongs to the sillimanite group, along with kyanite and sillimanite. It is a polymorphous mineral, meaning it can exist in several crystal forms. The most common form of andalusite is prismatic with a square cross-section, although it can also form in elongated or tabular crystals. Its color ranges from white, gray, yellow, green, brown, and red-brown. Its hardness is 7.5 on the Mohs scale, making it a durable mineral.

To identify andalusite, one can look for its distinctive cross-shaped crystal form. It can also be identified by its hardness and its color. Andalusite has a high refractive index, which means it can bend light at a greater angle than most other minerals. This property makes it useful in gemstone identification.

Andalusite has several uses, including as a refractory material in the production of ceramics, glass, and steel. It is also used as a gemstone due to its unique crystal form and color. Andalusite is a source of aluminum and is used in the production of aluminum metal. It is also used in the manufacturing of high-temperature materials, such as spark plugs and furnace linings.