Přírodovědné analýzy fajánsového korálku z hrobu nitranské kultury ze Slatinic, okres Olomouc
| Title in English | Natural scientific analyses of a faience bead from a Nitra-culture grave in Slatinice, district of Olomouc |
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| Authors | |
| Year of publication | 2006 |
| Type | Article in Periodical |
| Magazine / Source | Slovenská archeológia : [časopis Acheologického ústavu Slovenskej akadémie vied v Nitre] |
| MU Faculty or unit | |
| Citation | |
| Field | Archaeology, anthropology, ethnology |
| Keywords | Faience; frit; Nitra Culture; Egypt; optical polarization microscopy; SEM; EMPA; EDS; copper; cobalt; colorant; plant ash |
| Description | Several turquoise-coloured faience beads were revealed from a female grave of the Nitra-culture burial ground near Slatinice. Finds of numerous faience beads occur in some graves in necropolises belonging to the Late Aeneolithic and Early Bronze Age. Natural scientific methods (optic and electron microscopy and microanalyses) help solve the question of faience beads origin - whether they were made by the Nitra culture bearers or they were imported from distant regions. Optic polarising microscopy is the basic study method. The faience bead was studied by a polarising microscope Olympus BX51, which enables separated and parallel study of minerals in passing and reflecting polarized light. Chemical composition was specified by an electron microscope Philips XL30, with joined energy-disperse spectrometer. The obtained results were nailed down by a study of polished cross section by an electron microanalyser Cameca SX100. Microscopic analyses proved that the faience bead under study from 95% consists of various in size fragments of sharp angular quartz which were glued together with a small amount of lime or clay and the bead was probably moulded. After it had been dried up, the bead was burnt at the temperature lower than 800 C. Then it was dipped into a glazing solution with copper oxides and then burnt again or annealed at higher temperatures. High up to very high, almost constant content of potassium and corresponding content of sodium are typical for intersticial glasses of faience and blue copper cores. In beads from Egypt the normalised K2O content in copper blue colours is 11.9 %. Compared with this, the MgO content is very low. These results make us presuppose that for production of faiences ash was used as a source of alkali that is very rich in potassium, poor in MgO and have neutral content of CaO. Results of realised analyses of finds from Slatinice prove that the artefact the most probably was not made by the Nitra culture bearers. Concordance between our results and data published to finds of faience artefacts from Egypt is remarkable. We have compared our measured data with chemical composition of younger Egyptian artefacts (around 1500 BC). The time gap of one or two hundred years makes no obstruction in this case, as the glass colouring as well as production of frits and faience artefacts is proved to have longer tradition. Hence we can state that in the Nitra culture period (1800-1600 BC) faience beads were desired trade article transported from Egypt probably. |
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