The compositional variation in a multi-coloured, zoned tourmaline from the Cruzeiro pegmatite, Brazil, reflects melt chemical evolution during the entire pegmatite differentiation. In uncontaminated granitic pegmatite systems such as that of Cruzeiro, the compositional evolution of tourmaline progresses from schorl to fluor-elbaite, rather than directly from schorl to elbaite, to reflect co-enrichment in Li and F during fractional crystallization.

The CaSiO₃ system exhibits structural complexity with various polymorphs under different pressure and temperature conditions. This study stabilizes a new high-pressure polymorph, parabreyite, via multianvil syntheses at 4–5 GPa and 600–800 °C. Parabreyite's triclinic structure, with distinct threefold tetrahedral rings, was solved using 3D electron diffraction and X-ray diffraction. Elastic properties, thermal expansion and Raman spectra differences with breyite were analyzed.