Rhodolite

Rhodolite
General
CategoryPyrope variety, nesosilicate
Formula
(repeating unit)
(Mg,Fe)3Al2(SiO4)3
Crystal systemCubic
Identification
Colorlight to dark purplish red through reddish purple
Cleavagenone, may show indistinct parting
Fractureconchoidal
Mohs scale hardness7.0–7.5
Lustergreasy to vitreous
Specific gravity3.84±0.10
Polish lustervitreous
Optical propertiesSingle refractive, often anomalous double refractive
Refractive index1.760+0.010
−0.020
Birefringencenone
Pleochroismnone
Dispersion0.026
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 was first described from Cowee Valley, Macon County, North Carolina.[2] The name is derived from the Greek "rhodon" for "rose-like", in common with other pink mineral types (such as rhodochrosite, rhodonite). This coloration, and the commonly inclusion-free nature of garnet from this locality, has led to rhodolite being used as a gemstone. Rhodolite like other varietal names is not officially recognized as a mineralogical term, but rather used as an accepted trade name.[3][4]

  1. ^ Gem Reference Guide. [Santa Monica, CA]: Gemological Institute of America, 1988. ISBN 0-87311-019-6.
  2. ^ Cite error: The named reference Mindat was invoked but never defined (see the help page).
  3. ^ Lind, Thomas; Henn, Ulrich; Milisenda, Claudio C. (1998). "Comparative investigation of rhodolite garnets from different provenances". Gemmologie (Journal of the German Gemmological Association). 47 (1): 53–59. ISSN 0948-7395.
  4. ^ Lind, Thomas (2015). "Crystal chemistry and colour of garnets of commercially relevant gemstone occurrences". Gemmologie (Journal of the German Gemmological Association). 64 (1–2): 1–41. ISSN 0948-7395.