Shirokshinite, K(NaMg2)Si4O10F2, is the analogue of tainiolite, K(LiMg2)Si4O10F2, with the M1 octahedron fully occupied by Na instead of Li. It was found in the Kirovskii underground apatite mine (Kukisvumchorr Mountain, ...
The insufficiently studied beryllium silicate sphaerobertrandite has been known since 1957. The present work presents new findings, verifies that the mineral is a valid species with a unique structure. The original name ...