Apparent polytypism in the Ruiz Peak ferric phlogopite

M. Nespolo, Y. Kuwahara

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

An example of apparent polytypism in micas, i.e. twinning of a polytype giving a diffraction pattern which simulates that of a different polytype with longer periodicity, is reported from the Ruiz Peak ferric phlogopite, which is well known for the large number of polytypes and twins already found. The X-ray diffraction pattern, precession method, may correspond to a 1M polytype twinned by reticular pseudo-merohedry, a 3T polytype, untwinned or twinned by complete merohedry, or a 1M-3T allotwin. The morphological observation under the polarising microscope clearly shows the presence of twinning with composition plane (001) (rotation twinning), ruling out the case of untwinned 3T polytype. The SPM observation of the surface reveals the presence of 10 Å steps, without interlacting pattern or multiple steps, indicating that the sample is a twin of 1M. The twin is law [310]π (or[31̄0]π), the twin index is 3, and the twin obliquity is 0.03°. The higher frequency of rotations twins, i.e. with composition plane (001), with respect to reflection twins, i.e. with composition plane (quasi) normal to (001), is discussed in terms of the crystal growth conditions.

Original languageEnglish
Pages (from-to)1047-1056
Number of pages10
JournalEuropean Journal of Mineralogy
Volume13
Issue number6
DOIs
Publication statusPublished - 2001

Fingerprint

polytypism
twinning
Twinning
phlogopite
Diffraction patterns
Chemical analysis
obliquity
precession
Crystallization
diffraction
periodicity
Microscopes
X-ray diffraction
crystal
X ray diffraction

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology

Cite this

Apparent polytypism in the Ruiz Peak ferric phlogopite. / Nespolo, M.; Kuwahara, Y.

In: European Journal of Mineralogy, Vol. 13, No. 6, 2001, p. 1047-1056.

Research output: Contribution to journalArticle

@article{d5e65fb009de481f8be76355d556df1a,
title = "Apparent polytypism in the Ruiz Peak ferric phlogopite",
abstract = "An example of apparent polytypism in micas, i.e. twinning of a polytype giving a diffraction pattern which simulates that of a different polytype with longer periodicity, is reported from the Ruiz Peak ferric phlogopite, which is well known for the large number of polytypes and twins already found. The X-ray diffraction pattern, precession method, may correspond to a 1M polytype twinned by reticular pseudo-merohedry, a 3T polytype, untwinned or twinned by complete merohedry, or a 1M-3T allotwin. The morphological observation under the polarising microscope clearly shows the presence of twinning with composition plane (001) (rotation twinning), ruling out the case of untwinned 3T polytype. The SPM observation of the surface reveals the presence of 10 {\AA} steps, without interlacting pattern or multiple steps, indicating that the sample is a twin of 1M. The twin is law [310]π (or[31̄0]π), the twin index is 3, and the twin obliquity is 0.03°. The higher frequency of rotations twins, i.e. with composition plane (001), with respect to reflection twins, i.e. with composition plane (quasi) normal to (001), is discussed in terms of the crystal growth conditions.",
author = "M. Nespolo and Y. Kuwahara",
year = "2001",
doi = "10.1127/0935-1221/2001/0013-1047",
language = "English",
volume = "13",
pages = "1047--1056",
journal = "European Journal of Mineralogy",
issn = "0935-1221",
publisher = "E. Schweizerbart'sche Verlagsbuchhandlung",
number = "6",

}

TY - JOUR

T1 - Apparent polytypism in the Ruiz Peak ferric phlogopite

AU - Nespolo, M.

AU - Kuwahara, Y.

PY - 2001

Y1 - 2001

N2 - An example of apparent polytypism in micas, i.e. twinning of a polytype giving a diffraction pattern which simulates that of a different polytype with longer periodicity, is reported from the Ruiz Peak ferric phlogopite, which is well known for the large number of polytypes and twins already found. The X-ray diffraction pattern, precession method, may correspond to a 1M polytype twinned by reticular pseudo-merohedry, a 3T polytype, untwinned or twinned by complete merohedry, or a 1M-3T allotwin. The morphological observation under the polarising microscope clearly shows the presence of twinning with composition plane (001) (rotation twinning), ruling out the case of untwinned 3T polytype. The SPM observation of the surface reveals the presence of 10 Å steps, without interlacting pattern or multiple steps, indicating that the sample is a twin of 1M. The twin is law [310]π (or[31̄0]π), the twin index is 3, and the twin obliquity is 0.03°. The higher frequency of rotations twins, i.e. with composition plane (001), with respect to reflection twins, i.e. with composition plane (quasi) normal to (001), is discussed in terms of the crystal growth conditions.

AB - An example of apparent polytypism in micas, i.e. twinning of a polytype giving a diffraction pattern which simulates that of a different polytype with longer periodicity, is reported from the Ruiz Peak ferric phlogopite, which is well known for the large number of polytypes and twins already found. The X-ray diffraction pattern, precession method, may correspond to a 1M polytype twinned by reticular pseudo-merohedry, a 3T polytype, untwinned or twinned by complete merohedry, or a 1M-3T allotwin. The morphological observation under the polarising microscope clearly shows the presence of twinning with composition plane (001) (rotation twinning), ruling out the case of untwinned 3T polytype. The SPM observation of the surface reveals the presence of 10 Å steps, without interlacting pattern or multiple steps, indicating that the sample is a twin of 1M. The twin is law [310]π (or[31̄0]π), the twin index is 3, and the twin obliquity is 0.03°. The higher frequency of rotations twins, i.e. with composition plane (001), with respect to reflection twins, i.e. with composition plane (quasi) normal to (001), is discussed in terms of the crystal growth conditions.

UR - http://www.scopus.com/inward/record.url?scp=0035206417&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035206417&partnerID=8YFLogxK

U2 - 10.1127/0935-1221/2001/0013-1047

DO - 10.1127/0935-1221/2001/0013-1047

M3 - Article

AN - SCOPUS:0035206417

VL - 13

SP - 1047

EP - 1056

JO - European Journal of Mineralogy

JF - European Journal of Mineralogy

SN - 0935-1221

IS - 6

ER -