Zircon

File:Zircão.jpeg

Zircon crystal from Brazil.

Zircon is a silicate mineral. It is found in many different places in almost all kinds of rock. The chemical it is made up of is called zirconium silicate: ZrSiO₄. Clear zircon may look like diamond and has been used as a cheaper replacement for diamond. It is not the same as cubic zirconia, which is man-made zirconium dioxide. In the United States, zircon is considered to be the birth stone for the month of December.

Long lasting zircons

Zircon is very durable. It is hard and has a high melting point of around 2,500 °C (4,530 °F). Therefore it has survived for a very long time, even through metamorphic very warm processes deep underground, which otherwise melts or converts normal rocks.

Zircons from the Jack Hills in the Narryer Gneiss Terrane, Yilgarn Craton, Western Australia, have yielded U–Pb (uranium–lead radioactive dating) ages up to 4.404 billion years. This is judged 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 indicate that more than 4.4 billion years ago there was already water on the surface of the Earth. This interpretation is supported by additional trace element data, but is also the subject of debate.

Zircon Media

• Optical microscope photograph; the length of the crystal is about 250 μm

• Sand-sized grains of zircon

• A pale blue zircon gemstone weighing 3.36 carats

• This bracelet has zircon gemstones. The metal is zinc alloy base with silver coating.

• Zirconium mineral concentrates - world production trend.svg

  World production trend of zirconium mineral concentrates

• Zircon grain (CL-SEM imaging).tiff

  SEM-CL image of Zircon grain showing zonations and poly-cycles (core-rim structure)

• Zircon.GIF

  Crystal structure of zircon

• 

  Zircon Crystal

• Zirkon 372.jpg

  Scanning electron microscope image of zircon

• Zircon-tuc1001a.jpg

  Unusual olive-green zircon