EFR49CD4: Group of Borcarite crystals on matrix. This species is a curious combination of borate and carbonate - hence its name - with calcium and magnesium, of a delicate bottle-green color, with crystals that are among the sharpest and best developed known for the species, translucent and very lustrous.
A high quality specimen for the species.
San Bartolo Mine, Charcas, Municipio Charcas, San Luis Potosí  Mexico (2023)

Specimen size: 4 × 2 × 1.3 cm = 1.57” × 0.79” × 0.51”

Main crystal size: 0.2 × 0.1 cm = 0.08” × 0.04”