There are many studies on zircon, in the fields of the mineralogy, geochemistry, geochronology etc. My aim is not to cover all the zircon studies here, but only to present some of geochemical features  and some isotopical characteristics of zircon to stress on the scientific importance of this mineral.

Zircon, ZrSiO₄  the mineralogy

Zircon is a widely distributed accessory mineral in igneous rocks, it is a fairly common detrital mineral in some sediments and is also found in metamorphic rocks. Well-crystallized varieties, both clear and coloured, have long been used as gem stones, the name zircon is very old and is believed to be derived from the Arabic zarqûn, in turn derived from Persian zar, gold, and gun, colour. Specific gravity of a normal zircon is 4.67, and cell dimensions a 6.6164, c 6.0150± 0.0005 Å , and O-O distances in the SiO₄ tetrahedra as 2.42 Å (two) and 2.73 Å (four) (Deer et al., 1962).  

Ditetragonal-bipyramidal, the struc­ture consists of chains of alternating edge-sharing SiO₄ tetrahedra and ZrO₈ triangular dodec­ahedra extending parallel to [001] and joined laterally by edge-sharing ZrO₈ dodecahedra. The SiO₄ tetrahedra are slightly elongated along the c axis thus turned into tetragonal bisphe­noids. The c/a ratio is 0.909, underlining a typical pseudoi­sometric atomic arrangement. The four-fold screw axes formally insist on an axial development along the e direction, but glide planes of symmetry, rather uniform bonds throughout the structure, and poor {101} and {100} cleavages make it a good example of the pseudoisometric.

Zircon is a mineral most favoured and studied morphologically, especially by petrologists, being ubiquitous in igneous, metamorphic rock, pegmatites and sedimentary rock. In the latter, it occurs usually as detrital grains or abraded crystals depending on source rock and transport. All crystals (euhedral, subhedral or anhedral) frequently display continuous (unzoned, zoned or sectorial) or discontinuous growth (Kostov, 1999).

 Reference:

Deer, W.A., Hawie, R.A. and Zussman, J., 1962. Rock Forming Minerals. Vol.1. Ortho- and Ring Silicates. Longmans, Green and London Co. Ltd.

Kostov, I. , 1999. Crystal Habits of Minerals. Bulgarian Academic Monographs, Sofia .

 GEOCHEMICAL CHARACTERISTICS OF ZIRCON 

 ISOTOPICAL CHARACTERISTICS OF ZIRCON