Next Article in Journal
Characterization of Coal Micro-Pore Structure and Simulation on the Seepage Rules of Low-Pressure Water Based on CT Scanning Data
Previous Article in Journal
Influence of Sulfobacillus thermosulfidooxidans on Initial Attachment and Pyrite Leaching by Thermoacidophilic Archaeon Acidianus sp. DSM 29099
Article Menu

Export Article

Open AccessArticle
Minerals 2016, 6(3), 77; https://doi.org/10.3390/min6030077

Agates from Kerrouchen (The Atlas Mountains, Morocco): Textural Types and Their Gemmological Characteristics

1
Faculty of Geology, Geophysics and Environmental Protection, Department of Mineralogy, Petrography and Geochemistry, AGH University of Science and Technology, 30 Mickiewicza av., 30-059 Kraków, Poland
2
Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, 30 Mickiewicza av., 30-059 Kraków, Poland
*
Author to whom correspondence should be addressed.
Academic Editor: Raymond M. Coveney
Received: 30 April 2016 / Revised: 6 July 2016 / Accepted: 7 July 2016 / Published: 26 July 2016
Full-Text   |   PDF [8768 KB, uploaded 26 July 2016]   |  

Abstract

Agate nodules from Kerrouchen (Khénifra Province, Meknés-Tafilalet Region) in Morocco occur in Triassic basalts and reach up to 30 cm in diameter. Monocentric, banded agates—mainly in pastel pink, grey, white and yellow—with infiltration canals (osculum) are observed. Raman microspectroscopy revealed that the agates mainly consist of low quartz and subordinately moganite with distinctive 460 and 501 cm−1 marker bands, respectively. Linear mapping indicated that moganite mainly concentrates in grey zones of the monocentric agate nodules. The other types, polycentric and pseudostalactitic agates, are usually brown and red and contain minerals such as hematite and goethite. They form both regular and irregular mosaics rich in ornamentation. Occasionally, aggregates of copper sulphides or titanium oxides (rutile) can also be observed. These minerals are sometimes accompanied by carbonaceous material marked by 1320 and 1585 cm−1 Raman bands. It seems that formation of agates from Kerrouchen was induced by Si-rich and Fe-moderate fluids. Copper sulphides, rutile, and carbonates (possibly calcite) were most likely incorporated during post-magmatic processes. The origin of solid bitumen can be the result of hydrothermal or hypergenic processes. View Full-Text
Keywords: agate; Kerrouchen; Morocco; colour pigments; microtexture agate; Kerrouchen; Morocco; colour pigments; microtexture
Figures

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Natkaniec-Nowak, L.; Dumańska-Słowik, M.; Pršek, J.; Lankosz, M.; Wróbel, P.; Gaweł, A.; Kowalczyk, J.; Kocemba, J. Agates from Kerrouchen (The Atlas Mountains, Morocco): Textural Types and Their Gemmological Characteristics. Minerals 2016, 6, 77.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Minerals EISSN 2075-163X Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top