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Copyright of Praehistorische Zeitschrift is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

C4AF is considered the least reactive main clinker phase, but its reactivity may be affected by adding supplementary cementitious materials (SCMs). Pure C4AF was synthesised in a laboratory furnace, and the role of silica fume without gypsum on its early hydration properties was monitored. Burning was carried out in four stages to achieve 99% purity of C4AF. Heat flow development was monitored by isothermal calorimetry over 7 days of hydration at 20°C and 40°C. The role of silica fume on hydrogarnet phase katoite (Ca3Al2(SiO4)3 –x(OH)4x x = 1.5–3) formation during early hydration was studied. Rapid dissolution of C4AF, formation of metastable C‐(A,F)‐H and its conversion to C3(A, F)H6 was evidenced by isothermal calorimetry as a large exotherm. Changes in microstructure during early hydration were documented by SE micrographs, EDS point analyses, X‐ray mapping and line scans by SEM‐EDS. The phase composition was characterised by DTA‐TGA and QXRD after 7 days of hydration. The katoite diffraction pattern is similar for the reference sample and sample with silica fume, but substitution in its structure can be revealed by X‐ray microanalyses. The composition of katoite is variable due to the various extent of substitution of 4OH− by SiO44− due to silica fume. LAY DESCRIPTION: The paper discusses the role of silica fume on katoite formation during early hydration of C4AF. Rapid dissolution of C4AF, formation of metastable C‐(A,F)‐H and its conversion to C3(A, F)H6 was evidenced by isothermal calorimetry. Changes in microstructure during early hydration were documented by SE micrographs and X‐ray mapping and line scans by SEM‐EDS. The phase composition after 7 days of hydration was characterised by DTA‐TGA and QXRD. The high mobility of Al and Ca and the low mobility of Fe in the relic microstructure is discussed in the paper. Although katoite has the similar diffraction pattern for reference sample and sample with silica fume, different degrees of substitution in its structure can be seen in the silica fume system using SEM X‐ray microanalyses. [ABSTRACT FROM AUTHOR]

Copyright of Archeologické Rozhledy is the property of Academy of Sciences of the Czech Republic, Institute of Archaeology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Horní Halže - Mýtinka is a mineral occurrence located near Mýtinka in the Krušné hory Mts. In the past, the area was intensively mined for iron (namely hematite in quartz veins). Quartz veins are located on complicated intersections of fault systems in mica schists and migmatites (Urban - Crkal 2021). Recently, Sejkora et al. (2021) described rich Cu mineralization found in the remains of old mine dumps. Sulfide mineralization is represented by pyrite, djurleite, roxbyite, anilite, spionkopite, bornite and covellite, supergene phases by malachite, brochantite, liebethenite and pseudomalachite. The studied material (thin blue coating on a part of a single sulfide grain 3 mm in size; Fig. 1) was found by the first author in 2021 at the old mine dump and matches the material described by Sejkora et al. (2021). The blue phase was identified as langite [Cu4(SO4)(OH)6 · 2H2O] using combination of EDS, Raman and pXRD. Chemical composition of examined mineral coating was analyzed using EDS, which detected presence of Cu, S and O contents only (with Cu significantly higher than S). Raman spectrum of langite from Mýtinka (Fig. 2, Tab. 1) was acquired using a HORIBA LabRam spectrometer and the data were processed using Systat PeakFit software. Proposed spectrum model is in very good agreement with empirical data (r2 = 0.992). Assignment of individual bands according to Martens et al. (2002, 2003) is proposed in Table 1. Raman spectrum of langite is similar to those of posnjakite [Cu4(SO4)(OH)6 · H2O] and wroewolfeite [Cu4(SO4)(OH)6 · H2O]. By combining (poorly and only partially presented) data of Frost et al. (2004) and Martens et al. (2002), following differences among these phases were identified. Bands at 155 and 258 (262 in this work) cm-1 are present in the Raman spectrum of langite but missing in that of posnjakite. The Raman spectrum of wroewolfeite is devoid of bands at 507 and 596 (500 and 598 in this work) cm-1, characteristic of langite, and at 511 and 596 cm-1, characteristic of posnjakite. About 15 fragments of the coating, 20-100 μm in size, were analyzed on Panalytical X'Pert powder XRD diffractometer. Only four diffraction maxima were obtained due to a very small amount of material available. Nevertheless, corresponding d-values are in a good agreement with data for langite (Tab. 2; Galy et al. 1984). [ABSTRACT FROM AUTHOR]

The diversity of colours is one of the most typical features of vernacular architecture. The submitted study deals with the research on the use of ultramarine on the Pannonian type of folk house, which could be found in central, southern, and south-eastern Moravia. The authors primarily proceed from the younger shift of the house. This featured, among other things, mainly the original transformation of stylistic elements, the façade segmentation, and the diversity of colours used on the frontages of residential buildings. Blue pigments were only barely available by the early nineteenth century, especially in the rural environment. The use of blue pigments flourished in vernacular architecture only after 1828, when the technique for the production of ultramarine was published. This was followed by industrial production of this pigment. The technique for the production of ultramarine, applied in the past, is described e. g. in the publication Tovární výroba barev [Factory Production of Dyes] by Jaroslav Milbauer from 1926. The treatise interconnects the cultural-historical and the technical level of the phenomenon under study. The material-analytical section is based on ethnological field research and an analysis of historical plasters using both physical-chemical methods of their identification and the knowledge of material engineering. Ethnological knowledge thus acquires a completely new dimension, and it is supplemented by new conclusions. At the same time, it is also a detailed analysis of the structure of ultramarine currently acquired on our market and an attempt at its laboratory synthesis. The result of the presented experiment with the production of blue pigment can be beneficial in practice for restoration purposes and professional analysis of historical plasters. [ABSTRACT FROM AUTHOR]