Zircon is a mineral belonging to the group of nesosilicates. Its chemical name is zirconium silicate and its chemical formula is ZrSiO4. A common empirical formula showing some of the range of substitution in zircon is 1–x4x–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. The name derives from the Persian zargun meaning gold-hued and this word is corrupted into jargoon, a term applied to light-colored zircons. The English word zircon is derived from Zirkon, which is the German adaptation of this word, yellow, orange and red zircon is also known as hyacinth, from the flower hyacinthus, whose name is of Ancient Greek origin. Zircon is ubiquitous in the crust of Earth and it occurs as a common accessory mineral in igneous rocks, in metamorphic rocks and as detrital grains in sedimentary rocks. Their average size in granite rocks is about 0. 1–0.3 mm, Zircon is also very resistant to heat and corrosion. Because of their uranium and thorium content, some zircons undergo metamictization, 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 structure is compromised. Zircon occurs in many colors, including brown, yellow, green, blue, gray. The color of zircons can sometimes be changed by heat treatment, common brown zircons can be transformed into colorless and blue zircons by heating to 800 to 1000 °C. In geological settings, the development of pink, red, and purple zircon occurs after hundreds of millions of years, color in this red or pink series is annealed in geological conditions above the temperature about 350 °C. Zircon is mainly consumed as an opacifier, and has known to be used in the decorative ceramics industry. Zircon is one of the key used by geologists for geochronology. Zircon is a part of the ZTR index to classify highly-weathered sediments, Zircon is a common accessory to trace mineral constituent of most granite and felsic igneous rocks. Due to its hardness, durability and chemical inertness, zircon persists in sedimentary deposits and is a constituent of most sands
A lustrous crystal of zircon perched on a tan matrix of calcite from the Gilgit District of Pakistan
Optical microscope photograph; the length of the crystal is about 250 µm.