florencite-(Sm)

{{Short description|Mineral of the plumbogummite group}}

{{infobox mineral

| name = Florencite-(Sm)

| category = Phosphate mineral

| image =

| imagesize =

| alt =

| caption =

| formula = {{Chem2|SmAl3(PO4)2(OH)6}}

| IMAsymbol = Flo-Sm{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}

| strunz =

| dana =

| system = Trigonal

| class = Hexagonal scalenohedral ({{overline|3}}m)
H-M symbol: ({{overline|3}} 2/m)

| symmetry = R{{overline|3}}m

| 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 =Repina, S.A., Popova, V.I., Churin, E.I., Belogub, E.V., and Khiller, V.V., 2014. Florencite-(Sm)—(Sm,Nd)Al₃(PO₄)₂(OH)₆: A new mineral species of the alunite-jarosite group from the Subpolar Urals. Geology of Ore Deposits 53(7), 564-574{{cite web|url=http://www.handbookofmineralogy.org/pdfs/florencite-(Sm).pdf |title=Florencite-(Sm) - Handbook of Mineralogy |website=Handbookofmineralogy.org |accessdate=2016-03-08}}{{cite web|url=http://www.mindat.org/min-42495.html |title=Florencite-(Sm): Florencite-(Sm) mineral information and data |website=Mindat.org |accessdate=2016-03-04}}

}}

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.{{cite web|url= http://www.mindat.org/min-1560.htm |title=Florencite-(Ce): Florencite-(Ce) mineral information and data |website=Mindat.org |accessdate=2016-03-09}}l Florencite-(Sm) is also a samarium-analogue of florencite-(La) (lanthanum-dominant) and waylandite (bismuth-dominant), both being aluminium-rich minerals.