Cesium

cesium

pollucite

fluorapophyllite-(Cs)

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Formula: Cs
Element, alkali metal, does not occur in the native state
Specific gravity: 1.873 at 20oC
Colour: Yellow/silvery
Melting point: 28.4oC
Boiling point: 670oC
Abundance: 3 parts per million by mass, 0.5 parts per million by moles in the Earth's crust, 8 parts per billion by Mass, 70 parts per trillion by moles in the Solar System (ChC).

Cesium is an extremely reactive metal and the most alkaline of the elements. It reacts explosively upon contact with water producing cesium hydroxide (CsOH), an extremely strong base that can rapidly corrode glass (ChC).

Cesium-bearing minerals include:

Oxides
cesiokenopyrochlore

Sulphates
cesiodymite

Vanadates
margaritasite

Phyllosilicates
fluorapophyllite-(Cs)
garmite

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