Rhodolite

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Rhodolite
Rhodolite in Matrix-Garnet Group Magnesium iron aluminum silicate Macon County North Carolina 2904.jpg
General
CategoryPyrope variety
Formula
(repeating unit)
(Mg,Fe)3Al2(SiO4)3
Identification
Colorlight to dark purplish red through reddish purple
Crystal systemcubic
Cleavagenone, may show indistinct parting
Fractureconchoidal
Mohs scale hardness7–7.5
Lustergreasy to vitreous
Specific gravity3.84 (+/− .10)
Polish lustervitreous
Optical propertiesSingle refractive, often anomalous double refractive
Refractive index1.760 (+.010, −.020)
Birefringencenone
Pleochroismnone
Dispersion.026
Ultraviolet fluorescenceinert
Absorption spectrausually at 504, 520, and 573 nm, may also have faint lines at 423, 460, 610, and 680–690 nm
References[1]
 
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Rhodolite
Rhodolite in Matrix-Garnet Group Magnesium iron aluminum silicate Macon County North Carolina 2904.jpg
General
CategoryPyrope variety
Formula
(repeating unit)
(Mg,Fe)3Al2(SiO4)3
Identification
Colorlight to dark purplish red through reddish purple
Crystal systemcubic
Cleavagenone, may show indistinct parting
Fractureconchoidal
Mohs scale hardness7–7.5
Lustergreasy to vitreous
Specific gravity3.84 (+/− .10)
Polish lustervitreous
Optical propertiesSingle refractive, often anomalous double refractive
Refractive index1.760 (+.010, −.020)
Birefringencenone
Pleochroismnone
Dispersion.026
Ultraviolet fluorescenceinert
Absorption spectrausually at 504, 520, and 573 nm, may also have faint lines at 423, 460, 610, and 680–690 nm
References[1]

Rhodolite is a varietal name for rose-pink to red mineral pyrope, a species in the garnet group. It is found in Cowee Valley, Macon County, North Carolina.[2] The name is derived from the Greek for "rose-like", in common with many pink mineral types (e.g. rhodochrosite, rhodonite), but rhodolite itself is not officially recognised as a mineralogical term. This colouration, and the commonly inclusion-free nature of garnet from this locality, has led to rhodolite being used as a semi-precious gemstone. Chemically, rhodolite is an iron-magnesium-aluminium silicate, part of the pyrope-almandine solid-solution series, with an approximate garnet composition of Py70Al30.

References[edit]

  1. ^ Gem Reference Guide. [Santa Monica, CA]: Gemological Institute of America, 1988. ISBN 0-87311-019-6.
  2. ^ http://www.mindat.org/min-6719.html mindat.org: Rhodolite