Subduction is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another and is forced or sinks due to gravity into the mantle.
Regions where this process occurs are known as subduction zones.
Geologists have been wrestling with this question for centuries, especially those pioneers in the Earth sciences (e.g.
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.
Zircons contain trace amounts of uranium and thorium (from 10 ppm up to 1 wt%) and can be dated using several modern analytical techniques.
Because zircons can survive geologic processes like erosion, transport, even high-grade metamorphism, they contain a rich and varied record of geological processes.
Color in this red or pink series is annealed in geological conditions above temperatures of around 400 °C.), one of the most refractory materials known.
Other applications include use in refractories and foundry casting and a growing array of specialty applications as zirconia and zirconium chemicals, including in nuclear fuel rods, catalytic fuel converters and in water and air purification systems.
Zircon is also very resistant to heat and corrosion.
Because of their uranium and thorium content, some zircons undergo metamictization.
Australia leads the world in zircon mining, producing 37% of the world total and accounting for 40% of world EDR (economic demonstrated resources) for the mineral.
Zircon has played an important role during the evolution of radiometric dating.
This is done using an integrated cathodoluminescence and scanning electron microscope.