A selection of 102 iron implements out of 567 from two rural settlements was considered to be submitted to metallographical studies. The selection criteria were chronological on the first place (7th to 11th centuries AD), and typological on the second (quotidian items were preferred to ornaments or weapons). Finally, the state and preservation of the item was a definitive criterion among the available candidates, and were systematically selected the ones which presented sound metal and whose integrity and preservation was not jeopardized by the sample extraction and posterior conservation. Prior to sampling, X-radiographs were obtained to assess the condition and to investigate the overall assemblage.
The samples were first examined in the as-polished state to investigate the distribution of slag inclusions and corrosion by SEM microscope. Once this task was completed, the blocks were re-polished to remove the gold coating and etched with nital to reveal objects microstructure and accomplish the metallographic analysis. In parallel 61 evidences of slag, furnace wall and ore from six different sites were analysed by microscopy (OM, SEM, XRF and XRD) to approach the chemical composition and mineral structure of the technical materials
Some preliminary results regarding few iron and steel implements from Zaballa were advanced in Larreina-García and Quirós Castillo (2018b). Essentially, the main conclusions of that paper are still in force: regardless of the chronology the majority of the assemblage (89 items) was forged from single pieces of low-carbon iron without posterior heat-treatment; cutting-edge tools were frequently cold-forged to enhance their hardness and durability; and composite tools, typically made by welding of steel onto an iron back, are scant in comparison. In all probability, the early medieval peasantry in Álava had access to a wide variety of common, iron-made implements, which were typically of modest quality but perfectly functional; higher quality pieces are less frequent. The items were occasionally repaired in the rural settlements, but were manufactured elsewhere while the iron was reduced by the indirect method in the nearby ironworks. The repetitiveness on the smelting and manufacturing technologies would suggest a common procedure if not a technological tradition which could spread several centuries.
Results have already been presented in international conferences, one at the very beginning of the project (XII Congreso Ibérico de Arqueometría, Burgos, Spain, October 2017), and other in the SAA annual meeting (Albuquerque, New Mexico, April 2019), and another paper has been published in Antiquity reports (Larreina-Garcia and Quirós Castillo 2018).
In addition, two more conferences are schedule in Hungary‒Archaeometallurgy in Europe, June 2019‒ and Spain ‒Archaeology of peasantry, October 2019, and two more papers with full results are in preparation.
