New Minerals Belmonteite and Fengruiite Discovered

Scientists have identified a new arsenate mineral, belmonteite (CaMn₂(AsO₄)₂(H₂O)₅·2H₂O), in the manganese ore deposits of Graveglia Valley in eastern Liguria, Italy. Its crystal lattice shows {010} layers of six‑fold coordinated Mn atoms decorated on both sides by (AsO₄) groups and Ca atoms, connected through hydrogen bonds. The genesis is linked to As‑rich oxidizing fluids circulating within the deposit. The name honors Donato Belmonte for his contributions to Ligurian mineralogy.¹

A second discovery came from Haopinggou Ag–Pb–Zn–Au deposit in eastern Qinling, China, where researchers described fengruiite, an Ag–Sb–Te sulfosalt with a unique tellurium‑rich structure that traps silver. This finding offers new insights into how silver concentrates in high‑temperature mineral‑forming fluids.¹

In related research, a novel experimental approach was developed to study lithium and boron transport and isotope fractionation during fluid–melt interaction in pegmatitic systems. Two melt reservoirs were connected only via a fluid phase to simulate late‑stage pegmatite formation. Results showed Li and B moved through the fluid at low rates; Li isotopes preferentially enriched the heavier ^7Li in the fluid relative to the melt.¹