Editing Hand axe (section)

====Tool stone and cortex====
[[File:Bifaz sobre lasca.png|thumb|{{center|Simple Acheulean hand axe made from a large quartzite flake (direction of knapping: lateral)}}]]
Hand axes are most commonly made from rounded pebbles or nodules, but many are also made from a large flake. Hand axes made from flakes first appeared at the start of the Acheulean period and became more common with time. Manufacturing a hand axe from a flake is actually easier than from a pebble. It is also quicker, as flakes are more likely to be closer to the desired shape. This allows easier manipulation and fewer [[Knapping|knaps]] are required to finish the tool; it is also easier to obtain straight edges. When analysing a hand axe made from a flake, it should be remembered that its shape was predetermined (by use of the [[Levallois technique]] or Kombewa technique or similar). {{cn|date=January 2025}}

The natural external cortex or ''rind'' of the tool stone, which is due to erosion and the physical-chemical alterations of [[weathering]], is different from the stone's interior. In the case of [[chert]], [[quartz]] or [[quartzite]], this alteration is basically mechanical, and apart from the colour and the wear it has the same characteristics as the interior in terms of [[Mohs scale of mineral hardness|hardness]], [[toughness]] etc. However, flint is surrounded by a [[limestone]] cortex that is soft and unsuitable for stone tools. As hand axes are made from a tool stone's core, it is normal to indicate the thickness and position of the cortex in order to better understand the techniques that are required in their manufacture. The variation in cortex between utensils should not be taken as an indication of their age.{{cn|date=January 2025}}

Many partially-worked hand axes do not require further work in order to be effective tools. They can be considered to be simple hand axes. Less suitable tool stone requires more thorough working. In some specimens the cortex is unrecognisable due to the complete working that it has undergone, which has eliminated any vestige of the original cortex.