Ferrorhodonite, CaMn3Fe[Si5O15], a new mineral species from Broken Hill, New South Wales, Australia

A structure hierarchy is developed for chain-, ribbon- and tube-silicate based on the connectedness of one-dimensional polymerisations of (TO4)n− tetrahedra, where T = Si4+ plus P5+, V5+, As5+, Al3+, Fe3+, B3+, Be2+, Zn2+ and Mg2+. Such polymerisations are described by a geometrical repeat unit (with ng tetrahedra) and a topological repeat unit (or graph) (with nt vertices). The connectivity of the tetrahedra (vertices) in the geometrical (topological) repeat units is denoted by the expression cTr (cVr) where c is the connectivity (degree) of the tetrahedron (vertex) and r is the number of tetrahedra (vertices) of connectivity (degree) c in the repeat unit. Thus cTr = 1Tr12Tr23Tr34Tr4 (cVr = 1Vr12Vr23Vr34Vr4) represents all possible connectivities (degrees) of tetrahedra (vertices) in the geometrical (topological) repeat units of such one-dimensional polymerisations. We may generate all possible cTr (cVr) expressions for chains (graphs) with tetrahedron (vertex) connectivities (degrees) c = 1 to 4 where r = 1 to n by sequentially increasing the values of c and r, and by ranking them accordingly. The silicate (sensu lato) units of chain-, ribbon- and tube-silicate minerals are identified and associated with the relevant cTr (cVr) symbols. Following description and association with the relevant cTr (cVr) symbols of the silicate units in all chain-, ribbon- and tube-silicate minerals, the minerals are arranged into decreasing O:T ratio from 3.0 to 2.5, an arrangement that reflects their increasing structural connectivity. Considering only the silicate component, the compositional range of the chain-, ribbon- and tube-silicate minerals strongly overlaps that of the sheet-silicate minerals. Of the chain-, ribbon- and tube-silicates and sheet silicates with the same O:T ratio, some have the same cVr symbols (vertex connectivities) but the tetrahedra link to each other in different ways and are topologically different. The abundance of chain-, ribbon- and tube-silicate minerals decreases as O:T decreases from 3.0 to 2.5 whereas the abundance of sheet-silicate minerals increases from O:T = 3.0 to 2.5 and decreases again to O:T = 2.0. Some of the chain-, ribbon- and tube-silicate minerals have more than one distinct silicate unit: (1) vinogradovite, revdite, lintisite (punkaruaivite) and charoite have mixed chains, ribbons and/or tubes; (2) veblenite, yuksporite, miserite and okenite have clusters or sheets in addition to chains, ribbons and tubes. It is apparent that some chain-ribbon-tube topologies are favoured over others as of the ~450 inosilicate minerals, ~375 correspond to only four topologically unique graphs, the other ~75 minerals correspond to ~46 topologically unique graphs.

Section: T 5 Chainsmentioning

confidence: 98%

A structure hierarchy for silicate minerals: chain, ribbon, and tube silicates

Day

Hawthorne

2020

“…In the simplified formula, two types of M cations with different coordination numbers are distinguished. At present, three valid mineral species belonging to this group are known, namely rhodonite defined as CaMn 4 [Si 5 O 15 ], ferrorhodonite with the idealised formula CaMn 3 Fe[Si 5 O 15 ] (Shchipalkina et al , 2017) and vittinkiite described in the present paper. A proposal on vittinkiite was submitted by us to the IMA–CNMNC in 2017, however, it could only be accepted as a mineral species after the approval of the nomenclature of the rhodonite group in August 2019.…”

Section: Introductionmentioning

confidence: 78%

“…The polyhedron M 4 is a strongly distorted octahedron with the shortest and the longest cation–oxygen distances in the ranges 1.95 to 1.99 Å and 2.77 to 2.91 Å, respectively. This site concentrates Fe, Mg and Zn (Peacor and Niizeki, 1963; Ohashi and Finger, 1975; Peacor et al , 1978; Nelson and Griffen, 2005; Leverett et al , 2008; Shchipalkina et al , 2017). The shortest M 4–O distances are observed in samples with the highest contents of cations smaller than Mn 2+ , namely Mg 2+ and Fe 2+ .…”

Section: Crystal Structure Of Vittinkiitementioning

confidence: 99%

“…

Fig. 5.Ratios of the major metal cations in minerals of the rhodonite group ( a ) and pyroxmangite–pyroxferroite series ( b ), based on literature (Sundius, 1931; Hietanen, 1938; Peacor and Niizeki, 1963; Momoi, 1964; Burnham, 1971; Ohashi and Finger, 1975; Peacor et al , 1978; Sapountzis and Christofides, 1982; Pinckney and Burnham, 1988; Nelson and Griffen, 2005; Shchipalkina et al , 2017; Brusnitsyn, 2000, 2013; 2015; Shchipalkina et al , 2016; and reference therein) and our data. In ( a ) samples with determined crystal structures are marked by filled circles: blue – rhodonite; light purple – vittinkiite; deep purple – synthetic analogue of the end-member vittinkiite; red – ferrorhodonite; green – Zn-rich variety of rhodonite (‘fowlerite’); and grey – Mg-enriched variety of rhodonite.…”

Section: Identification Of Pyroxenoids With the Idealised Formula Mnsio3mentioning

confidence: 99%

See 1 more Smart Citation

Vittinkiite, MnMn₄[Si₅O₁₅], a member of the rhodonite group with a long history: definition as a mineral species

Shchipalkina

Pekov

Чуканов

et al. 2020

Self Cite

“…The M (4)-centred polyhedron is a strongly distorted octahedron with the shortest and the longest cation–oxygen distances in the ranges 1.95–1.99 and 2.77–2.91 Å, respectively. The M (4) site is typically Mn 2+ -dominant and can host Fe, Mg and Zn (Peacor and Niizeki, 1963; Ohashi and Finger, 1975; Peacor et al ., 1978; Nelson and Griffen, 2005); in the Fe-richest sample, M (4) is Fe 2+ -dominant, and for that reason this mineral has been approved by the IMA–CNMNC as a distinct mineral species, ferrorhodonite (Shchipalkina et al ., 2017).…”

Section: The Rhodonite Groupmentioning

confidence: 99%

Crystal chemistry and nomenclature of rhodonite-group minerals

Shchipalkina

Pekov

Чуканов

et al. 2019

Self Cite

This paper presents the nomenclature of the rhodonite group accepted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA). An overview of the previous studies of triclinic (space group P$\bar{1}$) pyroxenoids belonging to the rhodonite structure type, with a focus on their crystal chemistry, is given. These minerals have the general structural formula VIIM(5)VIM(1)VIM(2)VIM(3)VIM(4)[Si5O15]. The following dominant cations at the M sites are known at present: M(5) = Ca or Mn2+, M(1–3) = Mn2+; and M(4) = Mn2+ or Fe2+. In accordance with the nomenclature, the rhodonite group consists of three IMA-approved mineral species having the following the general chemical formulae: M(5)AM(1–3)B3M(4)C[Si5O15], where A = Ca or Mn2+; B = Mn2+; and C = Mn2+ or Fe2+. The end-member formulae of approved rhodonite-group minerals are as follows: rhodonite CaMn3Mn[Si5O15]; ferrorhodonite CaMn3Fe[Si5O15]; and vittinkiite MnMn3Mn[Si5O15].