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Rock crystal is a high-quality quartz variety with an excellent aptitude for knapping. Although it is relatively uncommon, in certain geological contexts such as that of our case study, rock crystal can serve as the raw material for a substantial number of tools. Nevertheless, very little research has been devoted to the study of this material. This lack of interest may stem from a variety of sources, from the difficulty of analysing a translucent material to its direct attachment to the symbolic world. Here we propose a methodology for the microscopic analysis of rock crystal artefacts in order to establish a better approach for understanding the functionality of this raw material. We comprehensively analysed a series of experimental tools before use by means of different microscopic equipment (OLM with a Nomarski prism and SEM). After the initial documentation, the tools were used in a sequential experimental programme in order to monitor and document the development of use-wear traces. Fourteen experiments were conducted on different materials and with different actions in which the different use traces as well as their respective orientations and sizes were recorded over a series of established times. The set of experiments resulted in different associations of use-wear traces (striations, chipping, rounding and polish) characteristic of the various worked materials and actions employed. We also documented how a technical mark such as the lancet can provide functional information. This is due to the formation process of the mark by percussion or pressure. While lancets formed from the impact point on the ventral side are distributed radially, those created by flake removal follow the kinematics of the tool. Finally, we demonstrated that rock crystal is a material that offers great possibilities for use-wear analyses once a set of technical and functional associations of mark analyses have been determined. Furthermore, although OLM with a Nomarski prism proved to be highly suitable in the analysis of rock crystal, its combination with other techniques such as SEM can provide additional information. [ABSTRACT FROM AUTHOR]

In general, quartz and most of non-flint rocks have not been extensively studied from a functional point of view. Very frequently the definitions of micro-features connected with flint surfaces have been used to describe those encountered on non-flint tools. This circumstance has repeatedly posed serious methodological problems for evaluating the accuracy of functional results when analysing use-wear on quartz and quartzite implements. This is due to the intrinsic divergences in morphology and distribution of use-wear with regard to the different lithic raw materials. Even though important efforts to systematise use-wear features on quartz have been done almost since the beginning of the discipline, there continues to be confusion and lack of standardisation regarding terminology in this aspect. In this paper, we try to contribute to new insights in this research by means of selecting examples from an extensive experimental programme involving different raw materials: from rock crystal (the purest form of quartz found in nature) to vein quartz and quartzite, with the latter two materials extensively used for knapping throughout Prehistory and still poorly understood in terms of microwear. For data recording, we preferentially used sequential experiments and resorted to both Optical Light and Scanning Electron Microscopy. We focused our interest on describing the main groups of wear features. The results obtained allowed us to assess the different mechanical behaviours under the stressors induced by tool-use from a group of raw materials with the same chemical composition but very different in structure. Furthermore, we propose the revision of some terms commonly employed when documenting micro-wear on quartz and similar rocks, as well as recurring concepts coming from materials and geological sciences (e.g. tribology, quartz exoscopy...). [ABSTRACT FROM AUTHOR]

The use of quartz is well documented during prehistory, being the predominant raw material in the Upper Paleolithic sites located in NW Iberia. The prehistoric occupations from Sabor valley also present a preference for this lithology through the long occupation sequence, although a large range of regional and exogenous lithic raw materials are also knapped. Within the quartz varieties rock crystal seems to have an important role in some chronologies, especially since the Solutrean phase, regarding elongated products and small flake production. Several reduction strategies were applied to rock crystal although the unifacial exploitation from a 45° degree striking platform using the crystal natural edges as guidelines is the most common. Though there are some similarities within the use of this type of cores throughout the chronological sequence we can observe some differences, especially during the Early Mesolithic phase. In a regional perspective, it is possible to compare the quartz economy from occupations in Sabor valley to the ones from Côa valley, to the south, and discuss the role of rock crystal in Late Pleistocene inland human groups. It is clear that there was a technical ability to maximize a local lithic resource such as rock crystal which was exploited in order to achieve blanks similar to those obtained from flint cores. [ABSTRACT FROM AUTHOR]

Rock crystal appears relatively frequently in Late Prehistoric Iberian sites, especially in the form of micro-blades and knapping debris. With some exceptions, however, these finds have seldom been looked into in any detail, and therefore little is known about the technology involved in the use of this material, its social and economic relevance or its symbolic significance. In this paper we examine a collection of rock crystal artefacts recently found at Valencina de la Concepción (Seville, Spain), one of the largest 3rd millennium BC sites in Western Europe. Among the objects included in this study are a long dagger blade, twenty-five arrowheads and a core, all of which form the most technically sophisticated and esthetically impressive collection of rock crystal material culture ever found in Prehistoric Iberia. Through the analysis of the procedures and techniques applied in the production of these objects, the chemical characterisation of the raw materials through Raman spectroscopy and RTI image processing and the careful assessment of the archaeological contexts in which they were found, this paper makes a robust contribution towards the study of the role of rock crystal in Copper Age technology and society. Recent research suggest that Valencina was a major node in the circulation of exotic materials such as ivory, amber, cinnabar or flint in Copper Age Iberia, which provides a very good background to assess the relevance of rock crystal as a traded commodity. In addition we discuss the role of rock crystal as a marker of status in large megalithic monuments, as well as its possible symbolic connotations. [ABSTRACT FROM AUTHOR]