Category Phosphate mineral Strunz classification 8.AC.45 Space group R3c | Formula
(repeating unit) Ca9NaMg(PO4)7 Crystal system Trigonal | |
Crystal class Ditrigonal pyramidal (3m)
(same H-M symbol) | ||
Merrillite is a calcium phosphate mineral with the chemical formula Ca9NaMg(PO4)7. It is an anhydrous, sodic member of the whitlockite group.
Contents
Discovery and naming
The mineral is named after George P. Merrill (1854–1929) of the Smithsonian Institution. Merrill had described the mineral from four meteorites in 1915: the Alfianello, Dhurmsala, Pultusk, and Rich Mountain meteorites. The mineral was not recognized as distinct from whitlockite, however, by the IMA until 1975.
Occurrence
Merrillite is a very important constituent of extraterrestrial rocks. It occurs in pallasites, lunar rocks, martian meteorites, and many other meteorite groups.
References
Merrillite Wikipedia(Text) CC BY-SA