The first known stone tools came from Africa and date back beyond the Pleistocene, or Ice Age, more than one million years ago. These were the pebble tools used by the Australopithecines. They were made of crudely shaped lava or quartz pebbles a little larger than a man's fist. Sometimes the pebbles were broken or chipped on two sides to form a simple cutting or scraping instrument. If you came upon any of these early stone tools you might easily mistake them for bits of battered rock shaped by the weight of the earth, the effect of frost, or the scraping of gravel and pebbles. Stones splintered by fire or worn down by sandstorm often look as though they are the handiwork of man. However, stones worked by man bear the mark of systematic chipping and shaping. Their designer would seem to have been all thumbs, but despite their ragged and irregular edges you can make out the design. Each one of these ancient stone tools was made by an intelligent being who knew what he was doing, however crude the finished product.
Over a period of many thousands of years man became more skillful in chipping these pebbles. He learned the trick of knocking flakes off the edge first in one direction and then in the other. The sides or faces were trimmed to a point, making a roughly pear-shaped two-faced tool. We call these pear-shaped chunks of stone hand axes, but probably they had very little in common with our idea of an ax. Most likely the hand ax was not attached to a handle but was grasped in one or both hands and employed like a Boy Scout knife as an all-purpose tool to cut, scrape, and gouge. Man soon learned that some kinds of stone were better for hand axes than other. Flint was commonly used in western Europe, because it flaked easily and yielded a razor-sharp edge. In Mexico, South America, and Africa a shining volcanic glass called obsidian was employed.
For countless years many hunting people made their tools by knocking the flakes off a stone and using only the core. The flakes were tossed aside as so much waste. But time came when people realized they could make as good a tool with the flake as with a heavy core. A flake tool was made simply by knocking a flake of stone off a larger block. The trick was to shear the flake off in such a way that one edge was broad and sharp and, at the same, strong. Flakes, depending on their size and shape, could then be used for chopping, cutting, scraping, and as a spearhead. Since they were more efficient in cutting up the carcasses and skinning big animals, such bisons, rhinoceros, and mammoth, flakes tools were more popular during cold glacial periods, and core tools prevailed during warm interglacial periods.