Felsparipitoisia

Felsparipitoisia is a mineral species in the feldspar group that has been described in contemporary mineralogy. It is distinguished by the incorporation of titanium into the tetrahedral framework of the alkali feldspar structure, which can give a pale green to colorless appearance and a higher refractive index than typical potassic feldspars.

Occurrence and composition: Felsparipitoisia occurs in pegmatitic rocks associated with quartz, muscovite, and sometimes beryl, typically within granitic intrusions. The ideal solid solution can be represented as (K,Na)(Al,Ti)Si3O8, with Ti substituting for Al in part of the tetrahedra. Charge balance is achieved through coupled substitutions and minor vacancies. It forms at relatively high temperatures during late-stage crystallization and is commonly found as euhedral crystals up to several centimeters.

Physical properties: It has a Mohs hardness around 6, two cleavages, and a vitreous luster. Refractive indices are in the approximate range of 1.520 to 1.535. Color ranges from pale green to colorless, and it is transparent to translucent in thin sections.

Taxonomic status and significance: Felsparipitoisia is regarded as a high-temperature member of the alkali feldspar subgroup. Its titanium content provides a distinctive geochemical fingerprint, aiding geothermobarometric interpretations in granitic systems. Due to its rarity, it is not routine in identification, but it remains a topic of interest for mineralogical research and petrographic studies.