Rhodonite is a manganese silicate (SiO₃,) that is sometimes mistaken for rhodochrosite (MnCO₃). Although most examples are opaque and massive, the best examples are prized for their gemmy translucence and sharply defined crystal form. Unlike rhodochrosite, which is a manganese carbonate that develops in rhombohedral habits within hydrothermal veins, rhodonite crystallizes in the triclinic system, typically forming as thick, blocky to tabular prisms within metamorphosed manganese deposits. The difference in structure and habit makes rhodonite instantly recognizable to trained eyes.
The Mina do Morro Mine in Minas Gerais, Brazil is a small but extraordinary source of rhodonite. Though limited in production, this mine has yielded some of the most sharply crystallized and translucent rhodonites known, rivaling the best from the Ural Mountains and Broken Hill. This specimen exemplifies that quality; it consists of a pair of robust, interlocking crystals with perfectly developed prism faces and glassy luster. The clarity and precision of form, combined with the size and symmetry of the cluster, place it among the top Brazilian rhodonites. It represents both mineralogical rarity and an elegant expression of natural art.