Crystal system Trigonal | Formula(repeating unit) SmAl3(PO4)2(OH)6 Space group R3m | |
Crystal class Hexagonal scalenohedral (3m)H-M symbol: (3 2/m) Unit cell a = 6.972, c = 16.182 [Å]; Z = 3 | ||
Florencite-(Sm) is a very rare mineral of the plumbogummite group (alunite supergroup) with simplified formula SmAl3(PO4)2(OH)6. Samarium in florencite-(Sm) is substituted by other rare earth elements, mostly neodymium. It does not form separate crystals, but is found as zones in florencite-(Ce), which is cerium-dominant member of the plumbogummite group. Florencite-(Sm) is also a samarium-analogue of florencite-(La) (lanthanum-dominant) and waylandite (bismuth-dominant), both being aluminium-rich minerals.
Occurrence and association
Florencite-(Sm) was revealed in quartz veins in the Maldynyrd Range, Subpolar Urals, Russia. It associates with xenotime-(Y).
References
Florencite-(Sm) Wikipedia(Text) CC BY-SA