Up to 4% of hafnium is frequently found, replacing zircon. Commonly radioactive, as it contains uranium and thorium impurities. It can present an adamantine gloss.
It is studied strictly for its dating potential, through decay analysis of its radioactive elements.
Due to its high melting point, it is widely used in industry, as cast mold coating, or in block and brick manufacturing.
Source: MM Gerdau - Museu das Minas e do Metal -