Technology and Terminology of Knapped Stone - IRIT

Polyhedral and spheroidal shaping appears very early on, in the Oldowan period, and
endures throughout prehistoric times. It is however far less common than bifacial shaping, its
conceptual opposite.
Other shaping method s
Shaping can yield other products of varied morphology, triangular, square, rhomboidal,
etc., in cross-section, which are dependant upon different methods for their manufacture. Two of
these methods are described hereafter.
• Trihedral shaping
The terms trihedron, pick or trihedral pick designate artefacts that are both elongate and
robust, with one or both tip ends rough-hewn to form a crude triangular point, or else a narrow
chisel (fig. 17).
Picks can be made on any kind of blank. Actually, a large number of knapping schemes
are available to shape the point, depending on whether one or possibly two surfaces (natural
surface or fracture face) are preserved - they can then be used as striking platforms - or whether
all three faces are knapped. The base need not be systematically modified 49
.
The technique used is direct percussion with a hard hammer.
The trihedral pick, whose function eludes us, is not a very common artefact. It appears
at the very beginning of the Acheulean, but develops mainly in the Sangoan (African Lower/Middle
Palaeolithic transition); it is also documented in the Upper Palaeolithic - but in a "lighter"
version - and can be found in some Mesolithic cultures.
• "Quadragular" shaping
This method is not widespread. It is undoubtedly best exemplified by the preforms of the
so-called "square cross-section" stone axes (the cross-section actually is rectangular) of the
Danish Final Neolithic (fig. 18:1) (see following section), or by those of south-east Asian stone
axes.
Quadrangular shaping is mainly connected with preforms, with the exception of the
Danish Bronze dagger hafts, which are not further modified. The method requires to be very well
mastered technically, in particular where large-sized pieces are concerned. A clumsy removal
during the roughing out stage can - in a deferred but irretrievable way - jeopardize the ultimate
shaping stages or the polishing stage.
Preforms
A preform is the result of the particularly careful preparation of a roughout, preliminary
to the finishing phase during which one or more techniques are brought into play (fig. 47).
Finishing scarcely modifies the shape of the preform, and the main finishing techniques used are
percussion, pressure, polishing, and pecking. Heat-treating may occur at one point in the chaîne
opératoire, and the way in which the techniques are ordered is eminently variable (for instance
heat treatment followed by pressure, polishing followed by pressure, pecking followed by
polishing, etc.).
Four examples of chaînes opératoires that include preforms are developed below : two
archaeological examples, the comprehension of which has been largely dependant upon experimentation,
and two ethnographical examples taken from very different contexts, a testimony of
the enduring practice of stone-knapping and of its socio-economic and symbolic role.
49 Brézillon, 1968; Leroy-Prost, Dauvois, Leroy, 1981.
51