text: In many cases, different cultures leave their materials as the only records; which anthropologists can use to define the existence of such cultures. The progressive use of more sophisticated materials allows archeologists to characterize and distinguish between peoples.  This is partially due to the major material of use in a culture and to its associated benefits and drawbacks. Stone-Age cultures were limited by which rocks they could find locally and by which they could acquire by trading. The use of flint around 300,000 BCE is sometimes  considered the beginning of the use of ceramics. The use of polished stone axes marks a significant advance, because a much wider variety of rocks could serve as tools.
  The innovation of smelting and casting metals in the Bronze Age started to change the way that cultures developed and interacted with each other.   Starting around 5,500 BCE, early smiths began to re-shape native metals of copper and gold, without the use of fire and by using tools and weapons. The heating of copper and its shaping with hammers began around 5,000 BCE.  Melting and casting started around 4,000 BCE. Metallurgy had its dawn with the reduction of copper from its ore around 3,500 BCE.  The first alloy, bronze came into use around 3,000 BCE.