Albite
Albite is the sodium-rich end of the plagioclase feldspar series, found as small grains in equilibrated chondrites.
Albite is plagioclase feldspar at its sodium-rich end, NaAlSi3O8. On Earth it is common in granites and metamorphic rocks.
In ordinary chondrites, sodium-rich plagioclase is a sign of heating. Primitive, unequilibrated chondrites contain glass inside their chondrules rather than crystalline feldspar. As the parent asteroid warmed, that glass slowly crystallised into tiny plagioclase grains of roughly albite to oligoclase composition, around An10 to An12. The grains grow larger with more intense heating, so plagioclase size is one of the measures used to assign petrologic types 4, 5 and 6.
Albite also appears in some primitive achondrites and in a few unusual meteorites that contain sodium-rich, granite-like clasts. Because sodium is a moderately volatile element, finding a lot of albite in a meteorite tells scientists its source was not heated so strongly that the sodium escaped.
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