Fluorite Mineralization Research Articles

Fluorite Mineralization Related to Carbonatitic Magmatism in the Western Transbaikalia: Insights from Fluid Inclusions and Trace Element Composition

Fluorite mineralization associated with different types of magmatism is common in the Western Transbaikalia. This study deals with Arshan, Yuzhnoe, and Ulan-Ude fluorite occurrences, which are the most significant examples of carbonatite-related fluorite mineralization in the region. The present paper focused on new fluorite geochemistry and fluid inclusion data, is aimed at revealing conditions of the fluorite mineralization formation, highlighting its genetic relationship with magmatism, compared to other deposits of this type. All the three locations belong to the Late Mesozoic Central Asian carbonatite province. Fluorites here are characterized by high rare earth elements (REE), Sr, and elevated La/Yb values. Fluid inclusions data imply that the formation of fluorite mineralization is a long process extending from late magmatic to the hydrothermal stage. Early fluorite crystallized from sulfate-carbonate orthomagmatic fluids at temperatures up to 500 °C. True hydrothermal fluorite was formed from the same fluids that were probably mixed with meteoric waters, which caused the temperature to drop to below 420 °C and led to an increase in the chloride component. The REE compositions of fluorite from the studied locations are similar to compositions of REE-rich fluorites from carbonatite-related deposits around the world.

Origin of the Tongda fluorite deposit related to the Palaeo‐Pacific Plate subduction in southern Jiangxi Province, China: New evidence from geochronology, geochemistry, fluid inclusion, and H–O isotope compositions

The southern Jiangxi Province is an important part of the fluorite mineralization belt in South China. Fluorite ore bodies are primarily in the contact zone between the Devonian Huitong granitic complex and the Late Cretaceous Ganzhou Formation, controlled by the NE‐trending faults. Zircon U–Pb dating of the Huitong granitic complex yields emplacement ages of 410.7 ± 1.4 Ma and 400.7 ± 4.6 Ma, while the Sm–Nd dating of the fluorite yields an isochron age of 94 ± 2 Ma, suggesting that the Huitong granitic complex is the host rock. Fluid inclusions in the fluorite show low homogenization temperatures (136–207°C), salinities (1.23–3.87 wt% NaCl), and densities (0.87–0.95 g/cm3), suggesting that the ore‐forming fluid is an NaCl‐H2O system of low temperature, salinity, and density. Raman spectroscopy showed that the fluid phase is dominated by water. The δDVSMOW values of the fluid inclusions in the Tongda fluorite ranged between −59.5 and −55.2‰, while the δ18OVSMOW values of the fluorite ranged from −7.2 to −5.6‰. Collectively, the ore‐forming fluid is dominated by meteoric water, possibly with a minor contribution of hydrothermal fluid. Both the interaction with host rocks and the cooling of hydrothermal fluids are the likely mechanisms of underlaying fluorite precipitation at low temperatures. The mineralization occurred in extensional faults during the Late Cretaceous related to the subduction of the Palaeo‐Pacific Oceanic Plate.

Groundwater fluoride concentrations in the watershed sedimentary basin of Quetta Valley, Pakistan.

Litho-geochemical characteristics of low and high fluoride (F-) groundwater along with hydrological processes were investigated to delineate its genesis and enrichment mechanism in a watershed sedimentary basin. In this study, groundwater F- concentration ranged from 0 to 20mg/L with a mean and standard deviation of 2.8 and ± 3.7mg/L, respectively. Out of N = 87, 63% of samples exceeded the World Health Organization (WHO) limit of 1.5mg/L. The order of cationic and anionic dominance in groundwater samples with mean was found in decreasing order as Na+ > Mg2+ > Ca2+ > K+ and HCO3- > SO42- > Cl- > PO43- > NO3- measured in milligrams per liter. Groundwater chemistry changed from Ca-HCO3 to Na-HCO3 type and low to high fluoride as we moved from mountain foot towards the synclinal basin. Low fluoride groundwater reflected weathering, recharge, and reverse ion exchange processes with Ca-HCO3- and Ca-Mg-Cl-type water while high fluoride groundwater revealed base ion exchange, mixing, and desorption as dominant hydrological processes with Na-HCO3 and Na-Cl types of water. Gibb's diagram showed rock weathering and mineral dissolution as the major geochemical processes controlling water chemistry with an insignificant role of evaporation in the semi-arid area. Fluoride was undersaturated with mineral fluorite, indicating fluoride in groundwater is released by secondary minerals. However, due to complex geological features, groundwater fluoride enrichment was affected by a broad-scale process across a wide area such as depth, residence time, and most important geomorphological units hosting the aquifer.

Fluorite mineral waste as natural aggregate replacement in concrete

Fluorite mineral waste as natural aggregate replacement in concrete

Stability modeling of complex underground mine openings integrating point clouds and FEM 3D

The stability analysis of underground mine systems with complex 3D geometry is still a challenging task, especially when abandoned mines are planned for new uses with public access, that imply more restrictive safety requirements. This inherently multi-scale problem requires both the evaluation of the global mine stability and the assessment of local deformation and failure mechanisms of individual pillars or roof sectors in a robust 3D modeling framework. We integrated 3D remote survey techniques and FEM 3D modeling to perform a comprehensive stability analysis of an abandoned fluorite mine system in the central Southern Alps (Italy), including ten levels excavated in bedded limestones. We reconstructed the 3D geometry of three levels undergoing a reuse plan, combining a dynamic LiDAR system and close-range photogrammetry. We used point clouds in a workflow to generate solids, excavate the 3D analysis domain and generate a FEM 3D mesh for numerical modeling. We performed a series of continuum-based FEM 3D simulations of mine excavation and rock mass strength degradation. Our results allowed assessing the global stability of the abandoned mine and identifying critically stressed roof sectors and pillars to prioritize the local-scale analysis, remediation and monitoring of critical spots.

Determination of fluorine concentrations in mineralizing fluids of the Hansonburg, New Mexico Ba-F-Pb district via SEM-EDS analysis of fluid inclusion decrepitates

The Hansonburg, New Mexico district in the southwestern U.S.A. contains anomalously fluorite rich carbonate-hosted base metal sulfide deposits. A long-standing hypothesis for this fluorite enrichment is that the Hansonburg mineralizing fluids were correspondingly enriched in F relative to the typical sedimentary brines that formed carbonate-hosted base metal deposits.The purpose of the present study was to test this hypothesis by determining the F concentration in fluid inclusions hosted by drusy quartz that paragenetically overlaps fluorite. The fluid inclusions were thermally decrepitated creating evaporative solute mounds, which were then analyzed via scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS). Fluorine was detected in all evaporative solute mounds analyzed, equating to fluid inclusion F concentrations of 320 to 2500 ppm. These F concentrations are significantly greater than the F concentrations of tenth's to 10s of ppm F typical of sedimentary brines. Further, these high F concentrations indicate that the Hansonburg mineralizing fluid must have been very acidic during the time of fluorite mineralization with a pH of 1 to 2.4. This pH is much lower than the pH of 4.3 to 5.1 predicted in earlier studies and also much lower than the pH of 4 to 5.5 considered typical of carbonate-hosted ZnPb mineralizing fluids. High mineralizing fluid F concentrations in combination with low pH would have provided conditions favorable for the formation of the observed Hansonburg mineral assemblage, i.e. fluorite-barite rich and metal sulfide mineral poor.

Geochemical characterization and assessment of fluoride sources in groundwater of Siloam area, Limpopo Province, South Africa

Siloam’s groundwater is reportedly characterized by high fluoride. In response to the reported high incidence of dental fluorosis in the area, sources of elevated fluoride in the groundwater were investigated. Total fluoride (TF) was determined using Ion Chromatograph and Fluoride Ion Selective Electrode. The mineral composition of rocks and soils were determined using X-ray Fluorescence and X-ray diffraction, respectively. Results revealed that groundwater fluoride concentration ranged from 3.92 to 4.95 mg/L. Na-Cl water type was found to be dominant in the water samples. TF content of the rocks and soils ranged from 10 to 2000 mg/L. Leachates were obtained by making a slurry from the samples at a predetermined temperature and time. TF in leachates ranged between 0.27 and 14.88 mg/L and 0.05 to 10.40 mg/L at induced, and non-induced temperatures, respectively. The possible source of fluoride has been previously inferred to be caused by fluorite minerals occurring at greater depth. However, this study proves that fluoride decreases with depth and the elevated fluoride in the groundwater is caused by smectite-kaolinite clay, muscovite and chlorite minerals abundant in the area. Geothermal temperature exhibited by the groundwater in the area is a major factor enhancing the release of fluoride from the clay materials.

Measuring productivity in the extractive industries. Evidence from Spanish fluorite mining

The extractive industries, as the suppliers of essential raw materials, carry out activities that are fundamental to the development of modern societies. Therefore, how they are managed and administered is of the utmost importance. Optimizing these management procedures is often difficult, however, due to the highly specific nature of the extraction of non-renewable resources.The sustainable management of the process should begin on the extraction stage to efficiently utilize said resources. Total productivity indices are good indicators for measuring efficiency. This work proposes the construction of total productivity indices that break down productivity growth into its principal determinants. The elaboration of these indices takes into consideration the idiosyncratic nature of the industry, how the gradual depletion of the resources impacts upon productivity, and scenarios in which more than one principal output is generated.The methodology which is proposed in this paper is used to analyse fluorite mining in Spain. Based on the empirical analysis, the study shows how the depletion of resources and countervailing technological advances serve to determine the levels of productivity within the industry. In light of these results, policy implications are then discussed.

Basement aquifer evolution and the formation of unconformity-related hydrothermal vein deposits: LA-ICP-MS analyses of single fluid inclusions in fluorite from SW Germany

The main ore stage of three similar unconformity-related vein systems in the Schwarzwald, SW Germany spanning a period of activity of ~150 Ma, was investigated to understand the details of fluid penetration from overlying sediments/marine environment into the basement, their evolution as well as the processes involved in vein formation. To investigate temporal and spatial variations of the hydrothermal fluids responsible for mineralization, over 1650 fluid inclusions were analyzed by microthermometry. Of these, a total of 108 fluid inclusions (mainly in fluorite) were successfully analyzed by LA-ICP-MS. The fluid inclusions reveal a binary mixing trend between a CaCl2- and a NaCl-rich endmember. Independent of major element composition, the fluids are metal-bearing (e.g., up to ~100 mg/kg Ba, Pb, Zn, Ni and up to 10 mg/kg Ag), show high As (up to 1000 mg/kg) and low S (below the detection limit in most analyses). Over time, the mixed fluid shows a gradual decrease in CaCl2 and increase in NaCl with slightly decreasing total salinity.Based on earlier studies and geochemical arguments, the veins formed by anisothermal binary fluid mixing of two fluids, which both were originally derived from seawater and chemically modified through interaction with the basement and sedimentary rocks in different ways. This produced a gradual stratified basement fluid reservoir comprising a modified bittern/halite dissolution brine. The fluids involved in the vein formation are sourced from different depths of this modified bittern/halite dissolution basement brine reservoir: fluid A, a CaCl2-dominated, KCl-poor, deeper seated brine with a salinity of ~25 wt% CaCl2 + NaCl, and fluid B, an NaCl-dominated and KCl-richer brine situated at shallower depths in the crystalline basement with salinities of ~22 wt% NaCl+CaCl2. Based on the Na-Ca-K and NaK thermometers and on Rb/Cs systematics, fluid A records alteration of the Na-, K- and Ca-bearing feldspars of the host rocks; progressive alteration led to consumption of mainly Ca-rich plagioclase in contact with these basement brines. Accordingly, fluid B that subsequently entered the basement was only in equilibrium with alkali feldspars and clay minerals. This scenario produced a gradual change of fluid composition with depth that was pushed to greater depth over time.The source temperatures are estimated to ~250 °C while vein formation occurred at 100–170 °C, based on fluid inclusion homogenization temperatures. Thus, significant fluid cooling without abundant fluid mixing (and without major mineralization) must have occurred during fluid ascent (3–7 km, depending on the assumed geothermal gradient). Fluid mixing then resulted in the formation of the major gangue minerals fluorite, quartz, barite and calcite, while the locally confined sulfides must have formed due to an influx of sulfide into the binary mixed fluid. The process of fluid mixing is a rapid and turbulent process. This is recorded by a great diversity of fluid compositions (including ones close to the mixing endmembers) trapped within the same crystal. Compositional variations are even visible within individual fluid inclusion trails.

Timing of fluorite mineralization and exhumation events in the east Central Alborz Mountains, northern Iran: constraints from fluorite (U–Th)/He thermochronometry

AbstractThe recently developed fluorite (U–Th)/He thermochronology (FHe) technique was applied to date fluorite mineralization and elucidate the exhumation history of the Mazandaran Fluorspar Mining District (MFMD) located in the east Central Alborz Mountains, Iran. A total of 32 fluorite single-crystal samples from four Middle Triassic carbonate-hosted fluorite deposits were dated. The presented FHe ages range between c. 85 Ma (age of fluorite mineralization) and c. 20 Ma (erosional cooling during the exhumation of the Alborz Mountains). The Late Cretaceous FHe ages (i.e. 84.5 ± 3.6, 78.8 ± 4.4 and 72.3 ± 3.5 Ma) are interpreted as the age of mineralization and confirm an epigenetic origin for ore mineralization in the MFMD, likely a result of prolonged hydrothermal circulation of basinal brines through potential source rocks. Most FHe ages scatter around the Eocene Epoch (55.4 ± 3.9 to 33.1 ± 1.7 Ma), recording an important cooling event after heating by regional magmatism in an extensional tectonic regime. Cooling of the heated fluorites, as a result of thermal relaxation in response to geothermal gradient re-equilibration after the end of magmatism, or exhumation cooling during extensional tectonics characterized by lower amount of erosion are most probably the causes of the recorded Eocene FHe cooling ages. Oligocene–Miocene FHe ages (i.e. 27.6 ± 1.4 to 19.5 ± 1.1 Ma) are related to the accelerated uplift of the whole Alborz Mountains, possibly as a result of the initial collision between the Afro-Arabian and Eurasian plates further to the south.

The Niederschlag fluorite-(barite) deposit, Erzgebirge/Germany\u2014a fluid inclusion and trace element study

The Niederschlag fluorite-barite vein deposit in the Western Erzgebirge, Germany, has been actively mined since 2013. We present the results of a first comprehensive study of the mineralogy, petrography, fluid inclusions, and trace element geochemistry of fluorite related to the Niederschlag deposit. Two different stages of fluorite mineralization are recognized. Stage I fluorite is older, fine-grained, associated with quartz, and forms complex breccia and replacement textures. Conversely, the younger Stage II fluorite is accompanied by barite and often occurs as banded and coarse crystalline open-space infill. Fluid inclusion and REY systematics are distinctly different for these two fluorite stages. Fluid inclusions in fluorite I reveal the presence of a low to medium saline (7–20% eq. w (NaCl+CaCl2)) fluid with homogenization temperatures of 140–180 °C, whereas fluorite II inclusions yield distinctly lower (80–120 °C) homogenization temperatures with at least two high salinity fluids involved (18–27% eq. w (NaCl+CaCl2)). In the absence of geochronological data, the genesis of the earlier generation of fluorite-quartz mineralization remains enigmatic but is tentatively related to Permian magmatism in the Erzgebirge. The younger fluorite-barite mineralization, on the other hand, has similarities to many fluorite-barite-Pb-Zn-Cu vein deposits in Europe that are widely accepted to be related to the Mesozoic opening of the northern Atlantic Ocean.

Mineralogy and Permeability of Gas and Oil Dolomite Reservoirs of the Zechstein Main Dolomite Basin in the Lubiatów Deposit (Poland)

Permeability characterizes the ability of rocks to store and transport natural gas, crude oil and reservoir fluids. Permeability heterogeneity of reservoir rocks, including dolomites, results from overlapping geological and physicochemical processes. The permeability study of gas-bearing dolomites was carried out on the Lubiatów hydrocarbon deposit (Poland), located at the Ca2 carbonate platform toe-of-slope, which is a prospective area for hydrocarbon exploration in Europe. Due to the complicated rock textures and overlapping alteration processes, including secondary crystallization or dissolution of minerals, the permeability of the deposit is variable. Studies of dolomites from a depth of 3242–3380 m show high mineralogical diversity; the percentage of dolomite ranges from 79% to 95% with a variable content of other minerals: anhydrite, gypsum, quartz, fluorite, plagioclase and clay minerals. The porosity variability ranges from 4.69% to 31.21%, depending on the measurement method used. The mean permeability value is 35.27 mD, with a variation range of 0.9 to 135.6 mD. There is neither change in permeability with depth and mineral composition, nor a direct relationship between porosity and permeability.

Mineralogy of volcanic calciocarbonatites from the Trig Point Hill debris flow, Kerimasi volcano, Tanzania: implications for the altered natrocarbonatite hypothesis

AbstractA major debris flow, the Trig Point Hill flow, originating from Kerimasi volcano (Tanzania) contains numerous blocks of extrusive/pyroclastic carbonatites similar to those exposed at the rim of the currently inactive crater. The blocks of calcite carbonatite consist of: (1) large clasts of corroded and altered coarse grained calcite; (2) primary prismatic inclusion bearing phenocrystal calcite; and (3) a matrix consisting primarily of fine-grained prismatic calcite. The large clasts are inclusion free and exhibit a ‘corduroy-like’ texture resulting from solution along cleavage planes. The resulting voids are filled by brown Fe–Mn hydroxides/oxides and secondary calcite. The prismatic or lath-shaped phenocrystal calcite is not altered and contains melt inclusions consisting principally of primary Na–Ca carbonates which contain earlier-formed crystals of monticellite, periclase, apatite, Mn–Mg-magnetite, Mn–Fe-sphalerite and Nb-perovskite. Individual Na–Ca carbonate inclusions are of uniform composition, and the overall range of all inclusions analysed (wt.%) is from 28.7 to 35.9 CaO; 16.7–23.6 Na2O; 0.5–2.8 K2O, with minor SO3(1.1–2.2) and SrO (0.34–1.0). The Na–Ca carbonate compositions are similar to that of shortite, although this phase is not present. The Na–Ca carbonates are considered to be primary deuteric phases and not secondary minerals formed after nyerereite. Monticellite shows limited compositional variation and contains 2–4 wt.% MnO and 12 wt.% FeO and is Mn-poor relative to monticellite in Oldoinyo Lengai natrocarbonatite. Periclase is Fe-bearing with up to 13 wt.% FeO. Spinels are Cr-free, Mn-poor and belong to the magnetite–magnesioferrite series in contrast to Mn-rich spinels of the magnetite–jacobsite series occurring in Oldoinyo Lengai natrocarbonatite. The matrix in which the ‘corduroy’ clasts and phenocrystal calcite are set consists of closely packed small prisms of calcite lacking melt inclusions, with interstitial fine-grained apatite, baryte, strontianite and minor fluorite. Pore spaces are filled with secondary Mn–Fe hydroxides/oxides, anhydrite and gypsum. The hypothesis that flow-aligned calcite in volcanic calciocarbonatites from Kerimasi, Tinderet, Homa and Catanda is altered nyerereite is discussed and it is considered that these calcite are either primary phases or altered melilite. The nyerereite alteration hypothesis is discussed with respect to the volumetric and compositional aspects of pseudomorphism by dissolution–precipitation replacement mechanisms. This study concludes that none of the volcanic calciocarbonatites containing flow-aligned calcite phenocrysts are altered natrocarbonatite.

Fluorite and Other Minerals from the Suever Quarry, Delphos, Van Wert County, Ohio

The Suever quarry is located near the western edge of the Findlay Arch mineral district, at the eastern edge of Van Wert County, Ohio, and at the southwest corner of the town of Delphos, Washington...

Preconcentration of Iron, Rare Earth, and Fluorite from Bayan Obo Ore Using Superconducting Magnetic Separation

Bayan Obo ore contains mainly bastnaesite, monazite and associated iron, fluorite, calcite, dolomite, barite, and trace amount of columbite. Due to its complex mineral compositions and similar mineral properties, it is difficult to separate and obtain rare earth and fluorite concentrates with high purity by conventional magnetic separation and flotation. In this paper, a stepwise magnetic separation process comprised of wet permanent magnetic separation (PMS), wet electromagnetic separation (EMS), and superconducting magnetic separation (SCMS) was proposed to pre-concentrate iron, rare earth, and fluorite minerals from Bayan Obo ore. The results showed that iron, rare earth, and fluorite preconcentrates with high purity and low impurity content could be achieved, which might be helpful to shorten the technological process and improve the separation efficiency for the subsequent flotation of iron, rare earth, and fluorite minerals.

Fluorite and translucent beads in Iberian Late Prehistory

ABSTRACT This paper is a research contribution about translucent beads, with special attention to fluorite mineral used by the communities of Iberian Late Prehistory. We review the use and social significance of translucent beads in this period. The starting point for this study is the chemical (Raman spectroscopy, p-XRF, XRD and VIS/NIR) and contextual analysis of an important number of adornments inventoried here for the first time, as well as a review of archeological literature on transparent/translucent beads.

The role of the structures on the fluorite mineralization: Insight to fluid inclusion and alteration map of the Laal-kan fluorite deposit, NW Iran

The role of the structures on the fluorite mineralization: Insight to fluid inclusion and alteration map of the Laal-kan fluorite deposit, NW Iran

Ar-Ar geochronology and petrogenesis of the Mushgai–Khudag alkaline‑carbonatite complex (southern Mongolia)

The Mushgai-Khudag alkaline‑carbonatite complex, located in southern Mongolia within the Central Asian Orogenic Belt (CAOB), comprises a broad range of volcanic and subvolcanic alkaline silicate rocks (melanephelinite-trachyte and shonkinite-alkaline syenite, respectively). Magnetite-apatite rocks, carbonatites, and fluorite mineralization are also manifested in this area. The complex formed between 145 and 133 Ma and is contemporaneous with late Mesozoic alkaline–carbonatite magmatism within the CAOB. Major and trace element characteristics of silicate rocks in the Mushgai-Khudag complex imply that these rocks were formed by the fractional crystallization of alkaline ultramafic parental magma. Magnetite-apatite rocks may be a product of silicate-Ca-Fe-P liquid immiscibility that took place during the alkaline syenite crystallization stage. The Mushgai-Khudag rocks have variable and moderately radiogenic Sr (87Sr/86Sr(i) = 0.70532–0.70614), ƐNd(t) = −1.23 to 1.25) isotopic compositions. LILE/HFSE values and SrNd isotope compositions indicate that the parental melts of Mushgai-Khudag were derived from a lithospheric mantle source that was affected by a metasomatic agent in the form a mixture of subducted oceanic crust and its sedimentary components. The δ18OSMOW and δ18CPDB values for calcites in carbonatites range from 16.8‰ to 19.2‰ and from −3.9‰ to 2.0‰, respectively. CO covariations in calcites of the Mushgai-Khudag carbonatites can be explained by the slight host limestone assimilation.

Selective impurity removal and Cu upgrading of copper flotation concentrate by a spontaneously oxidative H2SO4 leaching process

The gradual decrease of global copper resources is among the most urgent challenges for the mining industry. Sustainable utilization of copper sulphide flotation concentrate from iron oxide copper gold (IOCG) deposits is often constrained by the impurity elements (e.g. U, Th and F) and high levels of gangue minerals (e.g. iron oxide/hematite, U-bearing minerals and fluorite). Herein, a spontaneous oxidative H2SO4 leach process (<100 °C) is proposed to selectively remove the penalty elements and upgrade copper sulphide concentrate from IOCG deposits. During H2SO4 leach, 87–92% of F element in the fluorite mineral was extracted and the dissolution of iron oxide/hematite minerals were enhanced by the elevated temperature at 60–90 °C. The released Fe3+ ions from iron oxide/hematite minerals worked as the spontaneous oxidant for dissolving U-bearing minerals and upgrading copper minerals. The results reveal that the H2SO4 leach in presence of dissolved Fe3+ effectively removed 88–97% U and 89–90% Th from U-bearing minerals. Meanwhile, the elevated temperature at 60–90 °C plays a critical role in the phase transformation of bornite to covellite in the presence of Fe3+. Another phase transformation of chalcopyrite to bornite was also significant at the higher temperature of 90 °C through the non-oxidative dissolution mechanism. During the spontaneous oxidative H2SO4 leach, the dissolution of gangue minerals and phase transformations of copper minerals successfully upgraded copper concentrate from 41.1 to 50.5 wt% at 90 °C, while copper dissolution was maintained at less than 7.7%.

Conditions for the crystallization of fluorite in the Mushgai-Khudag complex (Southern Mongolia): Evidence from trace element geochemistry and fluid inclusions

The Mushgai-Khudag complex is part of the Late Mesozoic Central Asian carbonatite province. Fluorite mineralization is manifested throughout the province, including the Mushgai-Khudag complex. We have investigated the geochemical features and fluid inclusions of fluorites from different types of fluorite-bearing rocks. Fluorite from quartz-fluorite rocks has rare earth element (REE) concentrations in the range of 10500−144300 ppm and the highest light REE contents, with (La/Yb)N = 56−960. Fluorite from the fluorite-apatite-celestine rocks has slightly lower REE enrichment, especially light REE content, with concentrations of 200−5900 ppm and (La/Yb)N = 18−204. Fluorite from the fluorite-calcite rocks is characterized by REE contents of 22−1100 ppm and a variable (La/Yb)N of 0.6−59. These variations in the fluorite REE composition from different types of rocks were probably caused by the fact that at elevated temperatures, fluorine-containing light REE complexes are more stable than fluorine-containing heavy REE complexes. The progressive enrichment of medium and heavy REEs in the latter fluorite is related to fluid evolution. The homogenization temperature and salinity values of fluid inclusions in the Mushgai-Khudag fluorites vary between 550 and 185 °C and from rather high to 2 wt.%, respectively. The parental fluids of the fluorite-bearing rocks evolved from quartz-fluorite rocks to fluorite-apatite-celestine rocks to fluorite-calcite rocks. The key component was changed from sulfate to carbonate-chloride along with the high to medium temperature decrease (∼500−245 °C).