{{Short description|Lead sulfate carbonate hydroxide mineral}} {{Infobox mineral | name = Susannite | boxwidth = | boxbgcolor = | image = Lanarkite, Susannite, Macphersonite-359326.jpg | imagesize = | alt = | caption = Susanite with macphersonite and lanarkite from the Susanna Mine, Leadhills | category = Carbonate minerals | formula = Pb<sub>4</sub>SO<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>(OH)<sub>2</sub> | IMAsymbol = Sus<ref>{{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}}</ref> | molweight = | strunz = 5.BF.40 | dana = | system = Trigonal | class = Rhombohedral ({{overline|3}}) <br/>H-M symbol: ({{overline|3}}) | symmetry = ''R''{{overline|3}} | unit cell = a = 9.07, c = 11.57 [Å]; Z = 3 | color = Colorless, white, pale green, pale yellow, brown | colour = | habit = Occurs as equant to acute rhombohedral crystals | twinning = | cleavage = {0001} perfect | fracture = | tenacity = | mohs = 2.5 - 3 | luster = Adamantine, resinous | streak = | diaphaneity = Translucent | gravity = 6.55 | density = | polish = | opticalprop = Uniaxial (anomalously biaxial) | refractive = 1.96 | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = <ref name=Webmin>{{WebMineral|url=https://www.webmineral.com/data/Susannite.shtml|title=Susannite|access-date=2026-02-02}}</ref><ref name=Mindat>{{Mindat|id=3833|name=Susannite|access-date=2026-02-02}}</ref><ref name=HBM>[https://www.handbookofmineralogy.org/pdfs/susannite.pdf Susannite] at Handbook of Mineralogy<!-- also a copy at http://rruff.geo.arizona.edu/doclib/hom/susannite.pdf --></ref><ref>[https://www.rruff.net/odr/rruff_sample#/odr/view/647480 Susannite] at RRUFF – Comprehensive Database of Mineral Data</ref> }}
'''Susannite''' is a lead sulfate carbonate hydroxide mineral. It has the formula Pb<sub>4</sub>SO<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>(OH)<sub>2</sub>. Susannite is the higher temperature phase of the two and forms above 80 °C when fluids oxidize the lead ore deposits. It is trimorphous with leadhillite and macphersonite.<ref name=HBM/>
Susannite crystallizes in the trigonal system. It is quite soft with a Mohs hardness of 2.5 to 3.0 and a relatively high specific gravity of 6.57. [[File:Wanlockhead beam engine - geograph.org.uk - 143986.jpg|thumb|upright|left|An old beam engine to dewater a lead mine at nearby Wanlockhead]]
It was discovered in 1827 in the Susannah Mine, Leadhills in the county of Lanark, Scotland.<ref name=Mindat/> In addition to the type locality in Scotland, it has also been reported from various locations in Germany, the Tiger Mine in Pinal County, Arizona, from Iporanga, Brazil, and the Tsumeb mine of Namibia.<ref name=HBM/> {{clear left}}
==References== {{Reflist}}
==External links== * [https://galleries.com/minerals/carbonat/susannit/susannit.htm Susannite (lead sulfate carbonate hydroxide)], Amethyst Galleries' Mineral Gallery * [https://www.mineralienatlas.de/lexikon/index.php/MineralData?lang=en&language=english&mineral=Susannit Susannite (Susannit)] at Mineralienatlas - Fossilienatlas
Category:Lead minerals Category:Carbonate minerals Category:Trigonal minerals Category:Minerals in space group 148
{{Carbonate-mineral-stub}} {{Commons category}}