What property primarily characterizes cassiterite?

Cassiterite is primarily characterized as a source of tin. This mineral is the chief ore from which tin is extracted, making it economically significant in the production of various tin-based products. The chemical formula of cassiterite is SnO2, indicating that it contains a high concentration of tin in its composition. The mining and processing of cassiterite are crucial in metallurgy, particularly in producing tin, which is used in soldering, plating, and the manufacture of alloys.

The other properties mentioned do not relate to cassiterite in the same way. For instance, cassiterite does not conduct electricity well, nor is it soluble in water, which are properties that do not define its primary characteristics. Additionally, it does not have pyrotechnic qualities, as it is not used in applications requiring combustion or explosive behavior. Thus, the defining property of cassiterite is its role as a major source of tin, highlighting its importance in both chemistry and industry.