» Also see: cubic zirconium. Zircon (including hyacinth or yellow zircon)'s a mineral belonging to the group of nesosilicates. Its chemical name's zirconium silicate and its corresponding chemical formula's ZrSiO4. Hafnium's almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon's tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, and green. Colorless specimens that show gem quality are a popular substit… (More on Zircon)