The Copper Age
The Copper Age (also known as the Chalcolithic and neolithic) is an epoch in the human development, the transition between the Neolithic and Bronze Age associated with the appearance of the first processed metal - copper. The term was coined in 1876 by the Hungarian archaeologist Ferenc Pula on an International Аrchaeological Congress and specifies the classification of Thompson, which said that the Bronze Age followed the Stone one directly.
The Copper Age period covers approximately 4000-3000 BC., and some areas of the world continues more, bwhile in others it is absent entirely. Generally the Chalcolithic is considered an early Bronze Age, but some scientists consider it a separate period. Copper tools were manufactured in this age, which although soft and fragile, were better and more precise than the previous stone ones. However, throughout this period the use of stone remained more common due to the still primitive method of extraction and processing of metals.
During tthe Copper Age the construction of a hierarchical social system and a greater division of labor was observed than in previous eras. The most important finding in Bulgaria from Chalcolithic era is the Varna Chalcolithic necropolis, iin which the oldest processed gold in the world was found.