Crystal-Chemical Observations and the Relation Between Sodium and H2O in Different Beryl Varieties

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F22%3A00128030" target="_blank" >RIV/00216224:14310/22:00128030 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.3749/canmin.2100050" target="_blank" >https://doi.org/10.3749/canmin.2100050</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3749/canmin.2100050" target="_blank" >10.3749/canmin.2100050</a>

Result language

angličtina

Original language name

Crystal-Chemical Observations and the Relation Between Sodium and H2O in Different Beryl Varieties

Original language description

Beryl (Be3Al2Si6O18) is a well-known mineral, most famously in its vivid green form of emerald, but also as a range of other colors. Prominent varieties of beryl aside from emerald include aquamarine, red beryl, heliodor, goshenite, and morganite. There has not been a significant amount of research dedicated to comparing the crystal-chemical differences among the varieties of beryl except in determining chromophoric cations. While the H2O content within structural channels of emerald has been explored, and the H2O content of individual beryl specimens has been studied, there has not yet been a study comparing the H2O content systematically across beryl varieties. In this study we consider single-crystal X-ray diffraction data and electron probe microanalyses of 80 beryl specimens of six primary varieties, to compare and contrast their crystal chemistry. Beryl cation substitutions are dominantly coupled substitutions that require Na to enter a structural channel site. The results indicate that with increasing Na content beryl varieties diverge into two groups, characterized by substitutions at octahedral or tetrahedral sites, and that the dominant overall cation substitutions in each beryl variety tend to be different in more than just their chromophores. We find that the relation between Na and H2O content in beryl is consistent for beryl with significant Na content, but not among beryl with low Na content. Natural red beryl is found to be anhydrous, and heliodor has Na content too low to reliably determine H2O content from measured Na. We determined equations and recommendations to relate the Na and H2O content in emerald, aquamarine, goshenite, and morganite from a crystallographic perspective that is applicable to beryl chemistry measured by other means. This research will help guide future beryl studies in classifying beryl variety by chemistry and structure and allow the calculation of H2O content in a range of beryl varieties from easily measured Na content instead of requiring the use of expensive or destructive methods.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10504 - Mineralogy

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Canadian Mineralogist

ISSN

0008-4476

e-ISSN

1499-1276

Volume of the periodical

60

Issue of the periodical within the volume

4

Country of publishing house

CA - CANADA

Number of pages

51

Pages from-to

625-675

UT code for WoS article

000861174800003

EID of the result in the Scopus database

2-s2.0-85138945043