Most commonly, the preferential use of one specific raw material led to the production of characteristic core forms, as the properties of that particular raw material determined the use of specific technological approaches or operational schemas. Pitchstone (Ballin 2009), for example, is characterized by a number of different properties, each of which resulted in the ubiquity or scarcity of certain core forms:
- the tendency to break into tabular pieces led to the formation of many small squat or cubic cores, frequently with a flat ‘back-side’ (this also characterizes chert);
- the exaggerated tendency of pitchstone blades to curve along their long axes led to the formation of small discoidal cores; and
- its brittleness made this raw material less suitable for hammer-and-anvil production, resulting in low numbers of bipolar cores.
Blades from the Burnetland Hill chert quarry pit near Biggar, South Lanarkshire. This picture shows how the presence of internal fault planes in chert to a degree determines the final shape of chert artefacts (courtesy of Tam Ward, Biggar Archaeology Group).
Quartz (Ballin 2008a) is generally considered a ‘difficult’ raw material, defined by intricate fracture patterns, which lead to many cores being rather chunky, and with quartz operational schemas being less sophisticated than contemporary schemas in other raw materials. One consequence of this was that, in many parts of north and west Scotland, bipolar approaches were preferred (eg, Lussa River on Jura; Mercer 1971 (‘chisels’); also Ballin 2002), although some pure or fine-grained quartzes (e.g., Shieldaig, Wester Ross; Ballin 2008) allowed more traditional platform techniques to be applied.
Where more than one raw material was available to prehistoric people, certain raw materials were commonly preferred for certain tasks or tool forms. Although ideology (like group identity and religion) may occasionally have played a role in connection with these choices, many of those preferences may simply express functionality, in the sense that specific raw materials produced particularly sharp cutting-edges (knives), or they may have been valued for their durability (scrapers). At Upper Palaeolithic Howburn in South Lanarkshire, certain raw materials were clearly preferred for certain tool forms, and those preferences may represent a complex mixture of ideological and functional choices (Ballin et al. 2010).