Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-26T18:35:29.147Z Has data issue: false hasContentIssue false
  • English
  • Français

Welshite, Ca2Mg4Fe3+Sb5+O2[Si4Be2O18], a new member of the aenigmatite group

Published online by Cambridge University Press:  05 July 2018

Paul B. Moore
Paul B. Moore*
Affiliation:
Department of the Geophysical Sciences, The University of Chicago, Chicago, Illinois 60637, U.S.A.
Get access Rights & Permissions [Opens in a new window]

Summary

Welshite, triclinic, Ca2Mg4Fe3+Sb5+O2 [Si4Be2O18], a = 10·28 Å, b = 10·69 Å, c = 8·83 Å, α = 106·1°, β = 96·3°, γ = 124·8°, P¯1 with pseudo-monoclinic cell am = 9·68(1) Å, bm = 14·77(2) Å, cm = 5·14(1) Å, βm = 101·5(2)°, c-centred, occurs as lustrous subadaman-tine, thick prismatic reddish-black crystals up to 3 mm in greatest dimension associated with roméite, adelite, swedenborgite, berzeliite, manganoan phlogopite, richterite in crystalline dolomite from Làngban, Sweden. Forms include b {010}, a{100}, k{130}, m{110}, j{021}, p{111}, q{121}, v{131}, r{¯111}, s{¯121}, t{¯131}, and v{¯141} (monoclinic setting). Streak pale-brown, hardness 6, specific gravity 3·77, fracture conchoidal, no cleavage, α = 1·81(1), γ = 1·83(1), 2E(obs.) ≈45°, no noticcable pleochroism.

Welshite is a new member of the aenigmatite-rhönite group and obtains from the substitution Sb5+→ Ti4+ and Be2+ → Al3+ in rhönite.

Type
Research Article
Information
Mineralogical Magazine , Volume 42 , Issue 321 , March 1978 , pp. 129 - 132
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1978

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Cannillo, (E.), Mazzi, (E.), Fang, (J. H.), Robinson, (P. D.), and Ohya, (Y.), 1971. Am. Mineral. 56, 427.Google Scholar
Flink, (G.), 1927. Geol. Fbren. Stockh. Férhandl. 49, 138.CrossRefGoogle Scholar
Machin, (M. P.) and Siisse, (P.), 1974. Neues Jahrb. Mineral. Monatsh. 1974, 435.Google Scholar
Merlino, (S.), 1970. Chem. Comm. 20, 1288.CrossRefGoogle Scholar
Moore, (P. B.), 1967. Canad. Mineral. 9, 301.Google Scholar
Moore, (P. B.), 1970a. Ark. Mineral. Geol. 5, 55.Google Scholar
Moore, (P. B.), 1970b. Mineral Record, 1, 154.Google Scholar
Walenta, (K.), 1969. Z. Kristallogr. 130, 214.CrossRefGoogle Scholar

A correction has been issued for this article:

Errata and Addenda