Description

Stone tools play a privileged role in archaeology as they are extremely durable, and they survive through most circumstances. Palaeolithic tools have survived for hundreds of thousands of years, enduring repeated Ice Ages and being washed down rivers, but we can still pick them up, see how were made and say things about their makers. Even for more recent periods, the effects of weather and ploughing over thousands of years means more often than not stone tools are the only surviving evidence for where people were living and what they were doing.
Flint is very hard, and this means that its edges can be incredibly sharp and resistant to wear. But just as important is its structure. It is mostly a silicon dioxide, as is sandstone or glass, but it has what is known as a crypto-crystalline structure. It is crystalline, but the crystals are so small that they do not deflect any force waves that travel through. Therefore, with a lot of skill, and a bit of luck, it is possible to control how it fractures, making it possible to shape lumps of flint and detach flakes of predetermined shape and size.