Structural interpretation of a new twin in staurolite from Coray, Brittany, France - Université de Lorraine
Journal Articles European Journal of Mineralogy Year : 2019

Structural interpretation of a new twin in staurolite from Coray, Brittany, France

Abstract

A new twin in staurolite has been recently reported from Coray (Brittany, France). From morphological measurements the twin plane has been identified as (202), which corresponds to twinning by reticular pseudomerohedry with index 3 and obliquity 0.97º. On the basis of the high-degree of lattice restoration, significantly higher than that in the other well-known twins in staurolite (Greek cross and Saint Andrews cross), one would expect a high probability of occurrence for this twin. Its rarity can be explained on structural bases. The interface corresponding to the twin plane corresponds to a highly disrupted coordination, where only half of the tetrahedra are restored. This makes a contact twin highly unlikely. The reported twin is actually a penetration twin, in which the irregular composition surface may have compensated, to some extent, the unfavourable structural match.
Fichier principal
Vignette du fichier
EJM_staurolite-authors-file.pdf (826.33 Ko) Télécharger le fichier
Origin Files produced by the author(s)
Loading...

Dates and versions

hal-02308215 , version 1 (08-10-2019)

Identifiers

Cite

Massimo Nespolo, Yves Moelo. Structural interpretation of a new twin in staurolite from Coray, Brittany, France. European Journal of Mineralogy, 2019, 31 (4), pp.785-790. ⟨10.1127/ejm/2019/0031-2849⟩. ⟨hal-02308215⟩
86 View
260 Download

Altmetric

Share

More