The archaeological site of Belovode, Serbia, has yielded which are the oldest safely dated remnants of copper metallurgy at high temperatures, a process intended to separate the red metal from the mineral.
While the oldest signs of copper manufacture date from Anatolian Neolithic, c. 10,000 years ago, these only used low temperature burning and surely worked only with native copper (metal found naturally without admixture). Other findings of early copper metallurgy are also from West Asia, c. 6500 years ago, reason why it was believed that this technology arrived to Europe from Asia. There are still many sites in the Middle East with copper metallurgy signs that are not well studied anyhow, so it is very possible that the East-West cultural transference process was that way anyhow.
Belovode is one of many sites of the Vinca culture, which along with Dimini (Northern Greece) and others may represent a second wave from Anatolia after the original Neolithic that coalesced at Thessaly more than one millenium earlier. The fact that pottery and art style changed quite radically and that Vinca-Dimini individuals have been shown to have a South Anatolian affinity on craniometric analysis, added to related cultural findings in that part of Anatolia (Can Hassan), still allows for copper metallurgy to have a West Asian origin. We will have to wait for more detailed studies in that area in order to clarify this.
Another issue would be if this kind of metallurgy alone allows for the use of the term Chalcolithic (literally "copper and stone" age). Much like Neolithic is not anymore defined by the presence of polished lithic tools but a much more decissive socio-economical fact: agriculture and animal husbandry, Chalcolithic is normally not defined only by the presence or absence of copper (and other soft metals') metallurgy but by socio-economical features such as clear division of labor and the appearance of hierarchies. However this meaning of the word is still not wholly consensual and, in particular, British prehistorians remain reluctant to use the term Chalcolithic for such period (Stonehenge and such) preferring Late Neolithic instead merely because lack of copper, gold and silver metallurgy.
In the mainland, often cultures without metal remains, such as Chassey-La Lagozza (SE France, North Italy and parts of Switzerland, arguably proto-Ligurians) are often said to be Chalcolithic because of the developed socio-economical behavior displayed and the contemporaneity with other equivalent European cultures which are undoubtedly Chalcolithic. Inversely this term is never used to describe West Asian Neolithic with some copper, specially because copper appears since very early in the Neolithic.
This case however can be most controversial. Typically Chalcolithic is considered to begin c. 5500 years ago in Europe, when the first hierarchical societies and complex economies with division of labor appear. But Vinca-Dimini has sometimes been argued to be a incipient hierarchical society since the beginning, which probably was some sort of invasion. This is far from totally clear anyhow.
Source: Science News: Serbian site may have hosted first copper makers.