cassiterite

This term is used exclusively within the specialized registers of geology, mineralogy, and mining. It describes a specific chemical compound (tin oxide) rather than a general category of rock, making it a technical term of art. In professional contexts, it is often discussed in relation to "alluvial deposits" or "hard-rock mining."

As a mineral name, it functions as an uncountable mass noun when referring to the substance in general. While one might refer to "cassiterite crystals" or "grains of cassiterite," the mineral itself is not typically pluralized in scientific literature.