Uranium dating zircon
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 common constituent of most sands.
For example, hafnium is almost always present in quantities ranging from 1 to 4%.Ancient zircon crystals discovered in Western Australia have been positively dated to 4.374 billion years, confirming their place as the oldest piece of Earth ever found, according to a new study.The research reported in the journal , means Earth began forming a crust far sooner than previously thought, following the giant impact event which created the Earth-Moon system 4.5 billion years ago.Colourless 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.
"If that happens, the places where the lead has been removed, will appear to be younger than they are, while places where the lead has migrated appear older," says Valley.