Zircon ( or ; including
hyacinth or yellow zircon) is a
mineral belonging to the group of
nesosilicates. Its chemical name is
zirconium silicate and its corresponding chemical formula is
ZrSiO4. A common empirical formula showing some of the range of substitution in zircon is (Zr
1–y,
REEy)(SiO
4)
1–x(OH)
4x–y. Zircon forms in silicate melts with large proportions of
high field strength incompatible elements. For example,
hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is
tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green. Colorless specimens that show gem quality are a popular substitute for
diamond and are also known as "Matura diamond".