Monazite
“The rare earth mineral that records time”
Monazite is a rare earth phosphate mineral found as an accessory in many igneous and metamorphic rocks. It concentrates thorium and uranium, making it one of the most important minerals for high-precision geochronology — and it's also a major ore of cerium and other rare earth elements critical for modern technology.
cerium lanthanum phosphate ((Ce,La,Nd,Th)PO₄)
Minas Gerais (Brazil), Kerala (India), Western Australia (heavy mineral sands), Madagascar, Idaho (USA), Scandinavia
5-5.5
Modern electron microprobe dating of monazite can determine the age of individual growth zones within a single grain — revealing multiple metamorphic events recorded in a crystal smaller than a grain of sand.
Test Your Knowledge
Why can monazite record multiple geological events within a single grain, unlike many other dating minerals?
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