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The Gemstone Almandine (Garnet)

Almandine is the most common form of the gemstone Garnet. The term Garnet describes a group name for several closely related minerals that form important gemstones, and Almandine is an individual member mineral of the Garnet group. Almandine is usually opaque and unfit for gemstones use; though the less common transparent to translucent forms make fine gemstones. In the gem trade, the term Almandine is rarely used on its own. It is either generically called "Garnet", or "Almandine Garnet".

Color

Red, Black

Hardness

7.5 - 8.5

Chemical Formula

Fe₃Al₂Si₃O₁₂

Mineral Class

Almandine (Garnet)

Additional Properties

Crystal System
Isometric

Refractive Index
1.780 - 1.810

Double Refraction
None

Transparency
Transparent to translucent

SG
4.3

Luster
Vitreous

Cleavage None. May exhibit parting.

All About

Almandine is almost invariably dark in color, and it forms dark red to reddish-brown Garnet gemstones. Almandine is the hardest form of Garnet, and a pure deep red is its most valuable color. Almandine Garnets are occasionally hollowed in their underside to allow more light to enter a stone, giving a cut gemstone a lighter appearance. If the bottom of an Almandine gemstone is covered by a jewelry setting, the only way to easily determine if it is hollow is by its lighter weight.

Uses

Almandine is cut into dark red Garnet gemstones and used in all forms of jewelery, especially rings, earrings, and pendants. Lesser quality Almandine is polished into cabochons and beads for use in bracelets and necklaces. Almandine is also tumbled into smooth irregular stones for jewelry. Very dark or heavily included Almandine garnets are cut and polished into cabochons, and asterism (in the form of a weak four rayed "star") is observable in Almandine garnets from certain localities.

Other Names

Varieties

Mozambique Garnet - Red Garnet from the African country of Mozambique, which produces fine quality Garnet gemstones. Mozambique Garnet is usually Almandine, but may also be Pyrope.
Star Garnet - Form of Almandine Garnet that exhibits asterism in the form of a four-rayed star.

Treatments & Enhancements

Garnet gemstones are not enhanced, and their colors are always natural.

The Gemstone Almandine (Garnet) Sources

Although Almandine is common worldwide, gem forms of Almandine are much less prevalent. Sources include India, Sri Lanka, China, Madagascar, Australia, Brazil, and the U.S. (Alaska, Idaho, North Carolina, and New York).

Similar Gemstones

Most dark red gemstones on the market are either Almandine or Pyrope Garnets. Almandine and Pyrope Garnets can be very difficult to distinguish from each other, though Almandine is usually the darker of the two and is heaver. Dark red Spinel and Rubellite Tourmaline can also resemble Almandine, and Ruby is usually a lighter red color.