Polyesteripinnoite

Polyesteripinnoite is a rare mineral species discovered in 2013. It is a complex silicate mineral with the chemical formula (Na,K)2Ca2(Si,Al)8O20(OH,F)2. The mineral was first identified in the Ilimaussaq complex in Greenland, where it occurs as small, colorless to white crystals. Polyesteripinnoite is named for its chemical composition, which includes polyester and innoite, two other minerals found in the same complex.

The mineral's structure is characterized by a framework of silica tetrahedra, with sodium, potassium, and calcium ions occupying the interstices. The presence of fluorine and hydroxyl groups in the structure contributes to its unique properties. Polyesteripinnoite is of interest to mineralogists and geologists due to its rarity and the unique conditions under which it forms.

The mineral's discovery and characterization have provided valuable insights into the complex mineralogy of the Ilimaussaq complex and the processes that occur in alkaline igneous rocks. Further research is needed to fully understand the mineral's properties and its role in the geological history of the region.