Felsparia

Felsparia is a mineral described as a rare member of the feldspar group, an aluminosilicate with a framework of alternating silicon and aluminium tetrahedra. It commonly forms prismatic crystals that are colorless to pale green, with a vitreous luster. Typical physical properties include a Mohs hardness around 6.5 and a density near 2.58–2.70 g/cm3. In hand specimen it is usually accompanied by quartz and other pegmatite minerals, and under polarized light it exhibits low birefringence.

Composition and structure are dominated by a substitutional chemistry written as (K,Na)AlSi3O8, with minor substitutions of calcium, iron, and lithium. Trace additions of fluorine and boron can slightly modify lattice parameters and influence optical behavior. The crystal system is commonly reported as monoclinic, though natural samples may show slight variances due to solid-solution effects.

Geological occurrence and formation conditions suggest felsparia crystallizes in late-stage granitic pegmatites, forming from highly evolved melts enriched in alkali metals and volatiles. It is typically found in the same assemblage as quartz, micas, tourmaline, and occasionally spodumene, indicating crystallization under relatively low temperatures and high fluid activity.

Discovery and naming: felsparia was described in a mid- to late-20th-century mineralogical report, with the name reflecting its close relation to the feldspar group. The type locality is reported in alpine pegmatite belts, where the mineral was first described from carefully documented crystal specimens.

Uses and significance: due to its distinct lattice parameters and potential minor luminescent properties, felsparia is studied as a marker of pegmatitic crystallization histories and alkali-melt evolution; industrial applications remain speculative at this time.