289 METALLOGRAPHIC EXAMINATION OF SILVER JEWELLERY FROM THE “LUMBEGARDEN“ CEMETERY Kristýna Kolářová, Jiří Děd, Estelle Ottenwelter INTRODUCTION The high fragmentation of part of the silver jewellery from the “Lumbe Garden” cemetery enabled us to proceed to deeper material investigation by metallographic examination, using available fragments which could not be rejoined with the artefacts. The goals of this research were to identify the mate- rial and techniques of soldering used by Early Medieval craftsmen to manufacture silver jewellery. The surface of the silver jewellery was heavily etched and modiied having gone through invasive chemical cleaning in the past by immersion in aqueous alkaline cyanide solutions. Most of the corrosion products and copper content present in the alloy and in the solder was leached by cyanides, leading to distorted results in surface analyses. Analyses conducted on the cross section of available fragments enabled us to have a better idea of the composition of the alloys and the possible solder techniques used. Moreover, it allowed for a deeper material identiication in analyses of observed particles as well as a description of the corroded material. The majority of available fragments belong to artefacts manufactured from thin sheets of silver produced by cold working and composed of different components soldered together (kaptorgy, gom- biky, beads, pseudoglobular earrings). The thinness of the sheet used to manufacture the artefacts, cumulated with effects of intergranular corrosion, as well as drastic past chemical treatment and inap- propriate handling, have led to the high state of fragmentation of these artefacts. Fig. 5/1: Intergranular issures (H5-5), SEM micro- graph (SE image, photo J. Děd). Obr. 5/1: Interkrystalické trhliny (perla H5-5), mikrosnímek z rastrovacího elektronového mikros- kopu (zobrazení SE, snímek J. Děd). Fig. 5/2: Intergranular fracture surface (H5-5), SEM micrograph (SE image, photo J. Děd). Obr. 5/2: Povrch interkrystalického lomu (perla H5-5), mikrosnímek z rastrovacího elektronového mikroskopu (zobrazení SE, snímek J. Děd). Metallography silver data oprava.indd 289 8.6.2015 12:57:02