Refers to the earliest phase of Bronze Age cultures, which developed differently in different regions, either from Chalcolithic or Neolithic technologies. It differs from the Middle and Late Bronze Age cultures primarily in metal assemblages and burial rites. It is characterized in part by the earliest experimentation with copper alloys to produce bronze, as well as the improvement of stone tools, and various other local cultural developments. Some scholars classify the Chalcolithic as the earliest phase of the Bronze Age.