Badania mineralogiczno-gemmologiczne oraz mikrotermometryczne spodumenów z kopalni Nilaw (Laghman, NE Afganistan)

The aim of the study was mineralogical-gemological and microthermometric analysis of color types of spodumenes (green spodumenes, kunzite) from the Nilaw mine (Laghman Province, Afghanistan). These minerals contain numerous fluid inclusions, both primary and secondary, as well as mineral ones. The analyses of fluid inclusion assemblages (FIA) in green spodumenes showed of temperatures of homogenization (into vapor phase) of carbon dioxide (ThCO2) varing from 27.1 to 27.8°C and total homogenization temperatures (ThTOT) of 252–271°C. Temperature of crystallization after correction varies from 370 to 430°C and pressure - from 1.16 to 1.44 kbar. Composition of brines (in mol%): H2O = 0.93–0.94, CO2 = 0.027–0.038, NaCl = 0.029-0.032, with salinities from 4.33 to 6.59 wt.% NaCl eq. was also calculated. For FIAs in kunzite, temperatures of homogenization of carbon dioxide (ThCO2) range from 27.0 to27.3°C, whereas total temperatures of homogenization (ThTOT) is 238–250°C. Values of Tcr are 300–334°C and Pcr - 0.81–1.12 kbar. Composition of brines (in mol%) is: H2O = 0.57–0.75, CO2 = 0.22–0.40, NaCl ca 0.02; and salinity 4.5–5.7 wt. % NaCl eq. The obtained results show that the studied minerals precipitated from medium-temperature and low-pressure hydrothermal solutions varying in chemical composition. New Polish terminology for English equivalents regarding petrography of fluid inclusions was also proposed.