Short answers, pulled from the story.
The Chalcolithic, also called the Copper Age or Eneolithic, was a prehistoric period characterized by the increasing use of smelted copper, occurring after the Neolithic and before the Bronze Age. It did not happen at the same time everywhere; in the Ancient Near East it began in the late 5th millennium BC and lasted about a millennium, while in Britain it lasted from roughly 2,500 to 2,200 BC.
The world's oldest securely dated evidence of copper smelting at high temperature comes from the site of Belovode on Rudnik mountain in Serbia, dating to around 5,000 BC. A copper axe from Prokuplje, also in Serbia, provides the oldest securely dated evidence of copper-making more broadly, at roughly 5,500 BC.
Ferenc Pulszky, a Hungarian scientist, put forward the concept of the Copper Age in the 1870s, based on the large number of copper objects found within the Carpathian Basin. John Evans later formalized the distinction between the Copper Age and the Bronze Age proper in 1881.
Chalcolithic combines two Greek words: khalkos, meaning copper, and líthos, meaning stone. The term came into widespread use around 1900 as a replacement for Eneolithic, which critics felt looked misleadingly like e-neolithic, or outside the Neolithic.
No. The Chalcolithic was absent in some regions, including Russia, where there was no well-defined Copper Age between the Stone and Bronze Ages. In East Asia, copper artifacts began appearing in the 5th millennium BC in cultures such as Jiangzhai and Hongshan, but were not widely used in that early stage.
Four main Chalcolithic farming communities flourished in India: the Ahar or Banas culture (2000-1600 BC), the Kayatha culture (2450-1700 BC), the Malwa culture (1900-1400 BC), and the Jorwe culture (1500-900 BC). All four shared painted pottery and copper use but each maintained a distinct ceramic design tradition.