Aborigines were the earliest culture to use stone tools.
They used stone axes & adzes as well as knives & scrapers.
Knives & scrapers were made from flakes of stone. The flakes had extremely sharp edges.
Flakes could be used for finishing wooden tools like spears & axe shafts or for working with animals skins.
Flakes blunted quickly and had to be replaced often.
From time to time you can find an Aboriginal Tool factory where flakes were manufactured. The discarded flakes can be found just as they were left, long ago.