Zircons from Jack Hills in the Narryer Gneiss Terrane, Yilgarn Craton, Western Australia, have yielded U-Pb ages up to 4.404 billion years, interpreted to be the age of crystallization, making them the oldest minerals so far dated on Earth.
In addition, the oxygen isotopic compositions of some of these zircons have been interpreted to indicate that more than 4.4 billion years ago there was already water on the surface of the Earth.
The crystal structure of zircon is tetragonal crystal system.
The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green.
Connected to internal radiation damage, these processes partially disrupt the crystal structure and partly explain the highly variable properties of zircon.
As zircon becomes more and more modified by internal radiation damage, the density decreases, the crystal structure is compromised, and the color changes.
Colorless specimens that show gem quality are a popular substitute for diamond and are also known as "Matura diamond".
The name derives from the Persian zargun meaning gold-hued. It occurs as a common accessory mineral in igneous rocks (as primary crystallization products), in metamorphic rocks and as detrital grains in sedimentary rocks.
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%.
Zircon is rare within mafic rocks and very rare within ultramafic rocks aside from a group of ultrapotassic intrusive rocks such as kimberlites, carbonatites, and lamprophyre, where zircon can occasionally be found as a trace mineral owing to the unusual magma genesis of these rocks.