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Geochemical studies of the Pinavand Fluorite Mines indicates that
fluorite has been deposited from a high salinity, typically low temperature
and Mg-rich fluid in two stages: Based on geothermometrical data, at the
first stage fluorites were formed at relatively high temperature (85-235Cº)
and accompanied by host rock replacement (in the form of epigenetic
dolomitization). The second stage of fluorite mineralization has occurred at
low temperature (65-115 ºC) and has formed lodes and vein-likes along the
breccia and fault zones. However, the salinity was relatively invariable (15-
23 wt% NaCl), suggesting salinity of fluorite-forming fluid was the same at
all occurrences. By studying of REE patterns and regarding to some ratios of
HREE to LREE, it could be observed that the first stage of fluorites was
enriched in LREE revealing mineralization has occurred in early stage of
crystallization .In contrast, the second stage of fluorites containing high
proportion of HREE were deposited in the last stages of crystallization
event. Based on the calculated (Yb/La), (Yb/Ca), (Tb/La) and (Tb/Ca) ratios,
two mechanisms could be proposed: assimilation (replacement) for the first
type fluorites and remobilization (rejuvinilization) for fluorites of the second
stage.

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The Kamar-Mehdi fluorite deposit is located 100 km southwest of Tabas in Tabas Block, Central Iran. There are five stratabound orebodies in the area exposing in carbonate rocks of Shotori Formation. The oldest unit is Shotori Formation dolomite of Triassic age that is emplaced in the core of Kamar-Mehdi Anticline. Folding direction in the area is N-S and normal faults with W-E direction have caused some dislocations. Based on field and microscopic evidences, three types of mineralization are identified: 1- Early Diagenetic mineralization which is observed as disseminated in fenestral porosity in Shotori Formation dolomicrites; 2- Late Diagenetic mineralization that occurs as open space filling in vein and veinlets and open spaces of Shotori Formation. 3- Vein mineralization which occurs along with normal faults in the study area. Fluid inclusions studies of late diagenetic mineralization and vein mineralization show that the fluids in the late diagenetic mineralization have salinities between 15 and 26 wt% NaCl equivalent and homogenization temperatures of 150-270°C. Fluid inclusions of the vein mineralization have salinities between 3.4 and 20.2 wt% NaCl equivalent and homogenization temperatures of 140-237 °C.

The present study, with consideration on the late diagenetic mineralization and comparing it with vein type fluid inclusions, shows that the diagenetic fluid inclusions have higher salinities and homogenization temperatures. All the evidences show that mineralization at Kamar-Mehdi fluorite deposit is related to Shotori Formation and it is regarded as a fluorite-rich Mississipy Valley Type deposit.

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KuhSefid Flourite deposit is located about 110 km south east of Mashhad. Geological units of the region related to Kashafroud Formation with Jurassic age. Most of fluorite mineralization can be seen along the faults with direction of north west-south east. Fluorite veins are differente in diameter of 2 to 2.5 m and length of 50 m. Hydrothermal solutions with maximum and minimum temperatures of 181⁰C and 125⁰C with the average temperature of 152⁰C in protraction of faults, cracks and fragments, have created mineral substance. Geological evidences, petrography, mineralization and homogeneous temperature of fluids inclusion, are the evidences that concluded the Fluorite mineralization as Epithermal.

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In order to understand the cause of coloration of fluorites, following experiments (UV-spectroscopy, irradiation by gamma ray and thermal bleaching) carried out on the colored and colorless fluorites from the mines of Mazandaran Province. All colored and colorless fluorites have absorption band in UV part of electromagnetic waves but deep-violet and brown fluorites have an absorption band in visible range, whereas colorless and white varieties have not shown any absorption bands. Irradiation of colorless fluorites by gamma-ray caused a new absorption bands in UV-visible range. Thermal bleaching of the deep-violet fluorite reduced its color to pale-pink color and also pale-violet colored fluorite changes to colorless ones. Chemically, deep-brown and deep-violet fluorites show (1) the maximum total concentration of rare earth elements (ΣREEs= 20 ppm), Y (9 ppm and 3.5 ppm for deep-brown and deep-violet fluorites, respectively) and (2) total concentration of radioactive elements (U+Th= 2.8 ppm and 7.9 ppm for deep-brown and deep-violet fluorites, respectively). Based on this study, lattice defects in crystal structure of fluorites due to U and Th decay were caused the color centers (F-centers) as most important cause of fluorite coloration. This was confirmed by gamma-ray irradiation and color bleaching experiments.