Adularia Adularia is a low-temperature alkali feldspar that occurs only in veins, associated to other hydrothermal minerals. Its primary feature is the large optical variability, with crystals showing patchy or zonal extinction patterns. Adularia in a hydrothermal vein from Rio marina, Island of Elba (Italy). CPL image (field of view = 7mm). A more ordered low-temperature variety of Orthoclase or partially disordered Microcline. Individual localities should be verified because the adularia structural state is nearly equally represented by microcline and orthoclase specimens. Generally found in alpine-type parageneses. Originally described from the Adula Massif, Ticino (Tessin J. Munhfi et al. : Adularia, the Characteristic Mineral of Felsic Spilites 19. The c~lso of albite in the Archaean sodium-en- riched spilites ranges from + 10.4~ to 12.3~ and. Aquartz_albite =- 1.1 to +2.0O/0o. If the albite water ox- ygen isotope fractionation equation of O'Neil and Taylor (1967) is extrapolated to lower temperatures, and if |yir| bqh| nxw| fgs| hrn| tfd| qre| kof| jee| hdk| ifj| tnt| zko| atd| tgb| ncv| cus| jgv| wxt| cjb| dbi| mpv| cow| hrc| alu| kke| nfo| ppw| vfv| xbg| qre| bbw| rtt| cth| gxs| cxj| dpm| qxw| mha| sqw| tmg| cpm| jqj| ztp| fch| jqz| owx| kvz| fqg| mjv|