Malaia garnet

Malaia garnet or Malaya garnet is a gemological varietal name for light to dark slightly pinkish orange, reddish orange, or yellowish orange garnet, that are of a mixture within the pyralspite series pyrope, almandine, and spessartine with a little calcium. The name Malaia is translated from Swahili to mean, "one coming from Malay archipelago". It is found in east Africa, in the Umba Valley bordering Tanzania and Kenya.[2]

Malaia garnet
General
CategoryVarietal name
Formula
(repeating unit)
(Mg,Mn)3Al2(SiO4)3 [1]
Crystal systemcubic [1]
Identification
Colorlight to dark slightly pinkish orange, reddish orange, yellowish orange
Cleavagenone, may show indistinct parting [1]
Fractureconchoidal [1]
Mohs scale hardness7 - 7.5 [1]
Lustervitreous [1]
Specific gravity3.78 - 3.85 [1]
Polish lustervitreous to subadamantine[1]
Optical propertiesSingle refractive, often anomalous double refractive [1]
Refractive index1.760 (+.020, -.018) [1]
Birefringencenone [1]
Pleochroismnone [1]
Ultraviolet fluorescenceinert [1]
Absorption spectrastrong lines at 410, 420, 430nm, that may merge to form cutoff below 435nm. Also some combination of lines at 460, 480, 504, 520, or 573nm.[1]

References

  1. (Gia), Gemological. Gem Reference Guide. City: Gemological Institute of America (GIA), 1988. ISBN 0-87311-019-6
  2. Garnet(Almandine, Rhodolite, Pyrope, Demantoid, Tsavorite, Hessonite, Grossular, Spessartine) Course notes at the Department of Geological Sciences, The University of Texas at Austin website, accessed January 27, 2007
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