View source for Yangite

{{Infobox mineral
| name        = Yangite
| category    =chain silicate
| formula     =PbMnSi<sub>3</sub>O<sub>8</sub>•H<sub>2</sub>O
| IMAsymbol   = Ygi<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>
| system      =triclinic
|class=pinacoidal| unit cell   =a = 9.6015(9) Å, b = 7.2712(7) Å, c = 7.9833(8) Å
α = 105.910(4)°, β = 118.229(4)°, γ = 109.938(5)°
| color       =colorless to pale brown
| habit       =bladed or platy
| twinning    =not observed
| cleavage    =perfect on {101}
|tenacity=sectile| mohs        =5
| luster      =vitreous
|birefringence=δ = 0.015| 2V          =77° (measured)
| streak      =white
| gravity     =4.14 g/cm<sup>3</sup> (measured) 4.16 g/cm<sup>3</sup> (calculated)
| solubility  =insoluble in water, acetone, or hydrochloric acid
| references  =<ref name=one>Downs, Robert T.; Pinch, William W.; Thompson, Richard M.; Evans, Stanley H.; Megaw, Lauren (2016-11-01). "Yangite, PbMnSi3O8·H2O, a new mineral species with double wollastonite silicate chains, from the Kombat mine, Namibia". American Mineralogist. 101 (11): 2539–2543. {{doi|10.2138/am-2016-5682}}. {{ISSN|0003-004X}}.</ref>
<ref name=two>"Yangite: Mineral information, data and localities". mindat.org. Retrieved 2019-12-04.</ref>
}}
'''Yangite''' (PbMnSi<sub>3</sub>O<sub>8</sub>·H<sub>2</sub>O) is a chain-silicate mineral, first discovered within the Kombat mine in [[Namibia]]. The mineral is named after Hexiong Yang, a researcher at the [[University of Arizona]]'s Department of Geosciences. Yangite was approved as a valid mineral species by the [[International Mineralogical Association]] in 2012.<ref name=two />
==Occurrence==
Yangite was initially found within a specimen taken from the Kombat mine, located in the [[Otavi Valley]], Namibia. The specimen was obtained from John Innes, a senior mineralogist of the [[Tsumeb Corporation]]. Yangite occurs in an ore defined as an [[epithermal]] association. This ore type forms with narrow veins composed of [[galena]], [[rhodochrosite]], [[helvite]], and [[Baryte|barite]].<ref name=one />
==Physical Properties==
Yangite is colorless, ranging to pale brown when exposed to transmitted light. The mineral has a [[vitreous luster]] and [[Streak (mineralogy)|streaks]] white. Yangite maintains a [[Mohs scale of mineral hardness|Mohs]] hardness of five, and demonstrates perfect cleavage along {101}. There is no evidence of [[crystal twinning|twinning]] or parting within the available specimens. Yangite is [[sectile]], commonly found with bladed or platy habit. The mineral is [[biaxial]], elongated up to 12&nbsp;mm in length along the [010] axis. Yangite is insoluble in several fluids, including water, [[acetone]], and [[hydrochloric acid]].<ref name=one />
==Chemical composition==
Yangite has a consistent chemical composition, determined using a CAMECA SX100 electron [[microprobe]]. Additionally, the presence of H<sub>2</sub>O was confirmed using structural determination and [[Raman spectroscopy|Raman]] spectroscopic measurements.<ref name=one /><ref name=two />
Elemental Weight Percent:
{| class="wikitable"
!element
!wt%
|-
|Pb
|42.08
|-
|O
|29.24
|-
|Si
|17.11
|-
|Mn
|11.16
|-
|H
|00.41
|-
|Total
|100.0
|}
==X-ray crystallography==
Yangite was analyzed by both powder and single-crystal X-ray diffraction. Data was collected using the [[Bruker]] X8 APEX2 CCD [[diffractometer]]. The diffraction data was influenced by severe peak overlap, leading to uncertainty in the resulting index.<ref name=one /><ref name=two />
Powder Diffraction Data:
{| class="wikitable"
!d-spacing
!intensity
|-
|7.379 Å
|100
|-
|6.648 Å
|48
|-
|3.717 Å
|44
|-
|3.517 Å
|38
|-
|2.992 Å
|38
|-
|2.949 Å
|40
|-
|2.917 Å
|65
|-
|2.907 Å
|55
|}
==Crystal structure==
The chain silicate structure is formed by double [[wollastonite]] chains. These [[tetrahedral]] formations run parallel with the [010] axis and connect with Mn-polyhedra and Pb-polyhedra at the corners. The chains are also defined by four-membered and six-membered alternating tetrahedral rings. Yangite has three [[silicon|Si]] tetrahedral sites, defined as Si1, Si2, and Si3. Respectively, the average bond lengths are 1.622 Å, 1.622 Å, and 1.624 Å. Yangite is composed of an octahedrally coordinated Mn<sup>2+</sup> cation. Within the crystal structure, Pb<sup>2+</sup> has a coordination number of five, bonded with O molecules.<ref name=one />
==See also==
*[[List of minerals]]
==References==
{{Reflist}}
[[Category:Lead minerals]]
[[Category:Manganese minerals]]
[[Category:Inosilicates]]
[[Category:Triclinic minerals]]
[[Category:Hydrate minerals|1]]
[[Category:Minerals in space group 2]]