Andalusite

Andalusite
Andalusite is a strongly pleochroic gem which is largely unknown by the general public. It ranges in color from pale yellowish brown to dark green to dark brown.

Andalusite
The Andalusite gemstone has derived its name from a region in Spain known as 'Andulasia'. The uniqueness of the stone lies in the fact that it projects different colors when placed in different directions.

Andalusite
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Andalusite Facts and Buying Guide
This versatile gemstone strongly exhibits pleochroism.

Andalusite
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A hard silicate of alumina in rhombic crystals of a colour varying from pink to violet. More rarely, it may be red or green. Its main quality is its exceptional fire.

Andalusite
Cognac cocktail
Andalusite is named after Andalusia, the province of Spain where it was first discovered.

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.

Sources -- Brazil is the primary source. Gems are usually under 5 carats; stones over 10 carats are quite rare. An opaque variety of andalusite known as chiastolite is often cut in cross section to reveal a black cross on a gray background.

ANDALUSITE
Overview: Andalusite is named after Andalusia, the province of Spain where it was first discovered. Andalusite is a mineral, aluminum silicate, usually found in orthorhombic crystals of various colors.

Andalusite, 4.75 carats, Brazil
(Photo by ICA Bart Curren)
Andalusite is not a common stone, but it can be found by the gem enthusiast.

Andalusite, an aluminum silicate, derives its name from the site of its discovery, Almeria in the southern Spanish province of Andalusia.

Enhancements
Andalusite is not enhanced.
More information on gemstone enhancements.
Andalusite ...

Andalusite:
Andalusite is named after Andalusia, which is one of 17 autonomous communities that constitute Spain. It is characterized as a pleochroic gemstone, meaning that it has different colors as the stone moves in different directions.

Andalusite
Faceted andalusite stones give a play of red, green, and yellow colors that resembles a muted form of iridescence. Andalusite belongs to the same family as kyanite and sillimanite.

Andalusite is highly pleochroic gemstone, that is the angle of light refraction makes the wide array of colors seen in the stone. Typical colors include green, brown, red and yellow.

Andalusite
Named after Andalucia, Spain, where it was first discovered, andalusite displays many different colors; the angle of light refraction aids in the wide array of colors seen in the stone.

Andalusite
A polymorph with two other minerals, Kyanite and Sillimanite, Andalusite is an aluminum silicate.

Andalusite
Collector stone in the color range green to red brown
Hardness : 7-7.5 Refractive Index : 1.64 Density : 3.18
Angstroem unit
Unit to measure wavelengths for visible light and most X-rays. A=0.000001 mm ...

Andalusite"Makes collectible crossed crystals.
Anhydrite"What gypsum becomes deep underground.
Apatite"The phosphate mineral making up teeth and bones.

Andalusite is a highly prized collector's gemstone. It exhibits an optical property known as pleochroism. As the stone is turned or rotated, it exhibits different colors, or blends of colors depending on the angle of viewing.

Andalusite - An orangey brown, yellowish green or gold mineral, named after Andalusia, where it was first discovered. Sometimes called 'poor man's alexandrite'

Antique style - Process by which something takes on an aged look.

Andalusite ...See Kyanite, Sillimanite.^M
Varieties: Chiastolite, Viridine
Al2SiO5
Crystallography: orthorhombic
Colors: green, greenish brown w/ reddish tints chiastolite is impure variety showing gray cross on black or gray ground.
Hardness: 7.

Chiastolite (n) A metamorphic mineral, Chiastolite is a variety of Andalusite. It contains cross-shaped inclusions of carbon.
Cleavage (n) Describes an internal crack or break in a gemstone along a "cleavage plane".

Gemstone Physical Composition: Kyanite is a polymorph with two other minerals: andalusite and sillimanite. A polymorph is a mineral that shares the same chemistry but a different crystal structure with another, or other, minerals.

Sillimanite has the same chemical formula as both kyanite and andalusite (these three minerals are polymorphs); Sillimanite is the rarest of the three (all three are used in high-temperature ceramics, used in spark plugs).

This is a limestone matrix with andalusite crystals. It is also called Porphory. It received the name Chinese Writing Rock or Stone because of the crystalline structure resembling the Chinese characters of the written language.

These gemstones include amethyst, white opal, color change garnet, ametrine, peridot, andalusite, rhodolite garnet, citrine, blue topaz, iolite, chrome diopside, kunzite, and many ornamental gemstones such as turquoise, lapis lazuli, onyx, ...

A relatively large number of orthorhombic minerals are encountered with combinations of the various forms presented so far. These include andalusite, the members of the aragonite and barite group, brookite, chrysoberyl, the orthopyroxenes, goethite, ...

Color Change (gemstones) Color change gems change color due to changing light conditions (such as alexandrite or color change sapphire) or when viewed from different angles (such as andalusite or iolite).

This is usually related to the metamorphic temperatures of pelitic or alumonisilicate rocks and the minerals they form. The metamorphic grades of aureoles are andalusite hornfels, sillimanite hornfels, pyroxene hornfels.

5: Andalusite
Sec. IV, Ch. 6: Aquamarines or Beryl
Sec. IV, Ch. 7: Aventurine
Sec. IV, Ch. 8: Bloodstones
Sec. IV, Ch. 9: Carnelian
Sec. IV, Ch. 10: Chrysoberyl
Sec. IV, Ch. 11: Chrysoprase
Sec. IV, Ch.

Minerals characteristic of low- grade metamorphic environments include the zeolites, chlorites, and andalusite. Minerals character istic of high grade metamorphic environments include sillimanite, kyanite, staurolite, epidote, and amphiboles.

It has a specific gravity of 3.58. Kyanite is found in Brazil, Burma, Kenya, Europe, India, Australia, Kenya, and the USA. Kyanite's chemical composition is Al2SiO5; it is composed of andalusite and sillimanite.

There are even full treatments of lesser-known gems, from andalusite to vesuvian, and a special section is devoted to rocks as precious stones, including alabaster, onyx, obsidian, and fossils.

Unusual and rare stones from the same area include sillimanite, andalusite, scapolite, enstatite, kornerupine, diopside, and sinhalite.

See also: Stone, Crystal, Gemstone, Color, Jewel