florencite-(Sm)

{{infobox mineral | name = Florencite-(Sm) | category = Phosphate mineral | image = | imagesize = | alt = | caption = | formula = | IMAsymbol = Flo-Sm | strunz = | dana = | system = Trigonal | class = Hexagonal scalenohedral (m) H-M symbol: ( 2/m) | symmetry = Rm | unit cell = a = 6.972, c = 16.182 [Å]; Z = 3 | color = Colorless, pale pink, pale yellow | colour = | habit = Sub-mm zones in florencite-(Ce) crystals | twinning = | cleavage = {0001}, distinct | fracture = Uneven | tenacity = | mohs = 5.5-6 | luster = Vitreous to greasy | streak = White | diaphaneity = | gravity = | density = 3.6 (measured) | polish = | opticalprop = Uniaxal(+) | refractive = nω=1.70, nε=1.71 | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | references = }} 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).