almandine
Sign in to saveAlmandine (), also known as almandite, is a mineral belonging to the garnet group. The name is a corruption of alabandicus, which is the name applied by Pliny the Elder to a stone found or worked at Alabanda, a town in Caria in Asia Minor. Almandine is an iron aluminium garnet, of deep red color, inclining to purple. It is frequently cut with a convex face, or en cabochon, and is then known as carbuncle. Viewed through the spectroscope in a strong light, it generally shows three characteristic absorption bands.
Key facts
- Mineral.name
- Almandine
- Mineral.category
- Nesosilicate
- Mineral.boxbgcolor
- 5C4342
- Mineral.boxtextcolor
- white
- Mineral.class
- Hexoctahedral (mm) H–M symbol: (4/m 2/m)
- Mineral.symmetry
- Iad
- Mineral.color
- reddish orange to red, slightly purplish red to reddish purple and usually dark in tone
- Mineral.cleavage
- none
- Mineral.fracture
- conchoidal
- Mineral.mohs
- 7.0–7.5
- Mineral.luster
- greasy to vitreous
- Mineral.polish
- vitreous to subadamantine
- Mineral.opticalprop
- Single refractive, and often anomalous double refractive
- Mineral.birefringence
- none
- Mineral.dispersion
- 0.024
- Mineral.pleochroism
- none
- Mineral.fluorescence
- inert
- Mineral.absorption
- usually at 504, 520, and 573 nm, may also have faint lines at 423, 460, 610 and 680–690 nm
via Wikipedia infobox
Article
4 sectionsContents
- Occurrence
- Cultural significance
- See also
- References
Almandine (), also known as almandite, is a mineral belonging to the garnet group. The name is a corruption of alabandicus, which is the name applied by Pliny the Elder to a stone found or worked at Alabanda, a town in Caria in Asia Minor. Almandine is an iron aluminium garnet, of deep red color, inclining to purple. It is frequently cut with a convex face, or en cabochon, and is then known as carbuncle. Viewed through the spectroscope in a strong light, it generally shows three characteristic absorption bands.
Almandine is one end-member of a mineral solid solution series, with the other end member being the garnet pyrope. The almandine crystal formula is: Fe3Al2(SiO4)3. Magnesium substitutes for the iron with increasingly pyrope-rich composition.