Next Article in Journal
Role of Volcano-Sedimentary Basins in the Formation of Greenstone-Granitoid Belts in the West African Craton: A Numerical Model
Next Article in Special Issue
The Use of Infrared Spectroscopy to Determine the Quality of Carbonate-Rich Diatomite Ores
Previous Article in Journal
Determination of Seismic Safety Zones during the Surface Mining Operation Development in the Case of the “Buvač” Open Pit
Previous Article in Special Issue
Dissolution Behaviors of Trace Muscovite during Pressure Leaching of Hydrothermal Vein Quartz Using H2SO4 and NH4Cl as Leaching Agents
Article Menu
Issue 2 (February) cover image

Export Article

Open AccessArticle
Minerals 2018, 8(2), 72;

Investigation of Fluids in Macrocrystalline and Microcrystalline Quartz in Agate Using Thermogravimetry-Mass-Spectrometry

TU Bergakademie Freiberg, Institute of Mineralogy, Brennhausgasse 14, 09596 Freiberg, Germany
Helmholtz-Zentrum Dresden-Rossendorf, Helmoltz Institute Freiberg for Resource Technology, Chemnitzer Str. 40, 09599 Freiberg, Germany
Author to whom correspondence should be addressed.
Received: 3 November 2017 / Revised: 12 February 2018 / Accepted: 14 February 2018 / Published: 17 February 2018
(This article belongs to the Special Issue Mineralogy of Quartz and Silica Minerals)
Full-Text   |   PDF [14351 KB, uploaded 24 February 2018]   |  


Gaseous and liquid fluids in agates (banded chalcedony—SiO2) of different localities were investigated systematically by thermogravimetry-mass-spectrometry within a temperature range from 25 to 1450 °C, for the first time. Chalcedony and macrocrystalline quartz from twelve agate samples were investigated, from Germany (Schlottwitz, St. Egidien, Chemnitz and Zwickau), Brazil (Rio Grande do Sul), Scotland (Ayrshire) and the USA (Montana). They originate from mafic and felsic volcanic rocks as well as hydrothermal and sedimentary environments. The results were evaluated regarding compounds of hydrogen with fluorine, chlorine, nitrogen, carbon and sulphur. Additionally, oxygen compounds were recognized with hydrogen, fluorine, nitrogen, sulphur and carbon. The nature of the compounds was identified based on their mass-charge-ratio and the intensity ratios of the associated fragments. Due to interferences of different compounds with the same mass-charge-ratio, only H2O, HF, NO, S, SO, CO3—as well as several hydrocarbon compounds (for example CO32− or CO)—could be properly identified. The main degassing temperatures were detected at around 500 and 1000 °C. Generally, a difference between quartz and chalcedony regarding the composition of their fluids could not be found. The results indicate a silica source for the agate formation from aqueous solutions but also a possible role of fluorine compounds. Additionally, CO2 and other fluids were involved in the alteration of volcanic rocks and the mobilization and transport of SiO2. View Full-Text
Keywords: agate; quartz; chalcedony; thermogravimetry-mass-spectrometry; EGA agate; quartz; chalcedony; thermogravimetry-mass-spectrometry; EGA

Figure 1a

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).

Share & Cite This Article

MDPI and ACS Style

Richter-Feig, J.; Möckel, R.; Götze, J.; Heide, G. Investigation of Fluids in Macrocrystalline and Microcrystalline Quartz in Agate Using Thermogravimetry-Mass-Spectrometry. Minerals 2018, 8, 72.

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



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