AllMineralsRock
Andradite
Andradite is a popular gemstone (garnet) composed of calcium iron silicate. [1]
Andradite: Quick Facts and Characteristics
Some quick facts for Andradite:- Transparency: Andradite can be opaque, translucent or transparent.
- Luster: In terms of luster, andradite can be adamantine or submetallic.
- Streak: Andradite streaks colorless.
- Specific Gravity: Andradite's specific gravity ranges from 3.8 to 3.9.
Andradite: Background and Summary
Andradite is a mineral belonging to the garnet family. It is a calcium-iron garnet with the chemical formula Ca3Fe2(SiO4)3. Andradite is typically found in metamorphic rocks such as skarns and in hydrothermal deposits. It is also commonly found in igneous rocks such as kimberlites and carbonatites. Andradite is usually brown, green, or black in color, but can also be red or yellow.To identify andradite, one can look at its physical properties. Andradite has a hardness of 6.5-7.0 on the Mohs scale, making it relatively hard. It also has a high specific gravity, ranging from 3.8 to 4.2. Andradite is also strongly pleochroic, meaning that it appears different colors when viewed from different angles. In thin section, andradite appears brown or green with distinct cleavage.
Andradite has several uses in industry. It is used as an abrasive in sandpaper and as a refractory material. It is also used as a gemstone, although it is not as popular as other garnets such as almandine and pyrope. Andradite can be cut into faceted gems or used in cabochons. The green variety of andradite, known as demantoid, is particularly prized for its brilliance and fire.
Andradite: Table of Properties
| Attribute | Andradite (src) |
|---|---|
| Transparency | transparent, translucent, opaque |
| Chemical Formula | Ca3Fe3+2Si3O12 |
| Chemical Composition | calcium iron silicate |
| Specific Gravity | 3.8, 3.9 |
| Streak | colorless |
| Hydrous | No |
| Colors | common: red sometimes: gray, pink, black, brown, green, orange, yellow, multicolor |
| Fracture | 1: 1 |
Andradite: FAQ
Q: Is andradite radioactive?A: No, andradite is not radioactive.
Q: Is andradite rare?
A: Andradite is not considered rare, but high-quality gemstones can be relatively rare.
Q: Can andradite be found in jewelry?
A: Yes, andradite can be used in jewelry as a gemstone.
Q: What is the most valuable variety of andradite?
A: The green variety of andradite, known as demantoid, is the most valuable.
Sources
- Mindat.org- Gemological Institute of America (GIA)
- Andradite: https://en.wikipedia.org/wiki/Andradite
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