Cassiterite

 is mined from Tin deposits. It is used to craft and then smelted into s as part of.

In real life
Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite has been the chief tin ore throughout ancient history and remains the most important source of tin today.

Касситерит