Cardium Pottery or Cardial Ware is a Neolithic decorative style that gets its name from the imprinting of the clay with the shell of the cockle, an edible marine mollusk, formerly Cardium edulis, now Cerastoderma edule. These forms of pottery are in turn used to define the Neolithic culture which produced and spread them, mostly commonly called the "Cardial Culture".
The alternative name Impressed Ware is given by some archaeologists to define this culture, because impressions can be with sharp objects other than cockle shell, such as a nail or comb. Impressed pottery is much more widespread than the Cardial. Impressed Ware is found in the zone "covering Italy to the Ligurian coast" as distinct from the more western Cardial extending from Provence to western Portugal. The sequence in Western Europe has traditionally been supposed to start with widespread Cardial Ware, and then to develop other methods of impression locally, termed "epi-Cardial". However the widespread Cardial and Impressa pattern types overlap and are now considered more likely to be contemporary.
The Mediterranean Neolithic
This pottery style gives its name to the main culture of the Mediterranean Neolithic: Cardium Pottery Culture or Cardial Culture, or Impressed Ware Culture, which eventually extended from the Adriatic sea to the Atlantic coasts of Portugal and south to Morocco.
The earliest Impressed Ware sites, dating to 6400-6200 BC, are in Epirus and Corfu. Settlements then appear in Albania and Dalmatia on the eastern Adriatic coast dating to between 6100 and 5900 BC. The earliest date in Italy comes from Coppa Nevigata on the Adriatic coast of southern Italy, perhaps as early as 6000 cal B.C. Also during Su Carroppu civilization in Sardinia, already in its early stages (low strata into Su Coloru cave, c. 6000 BC) early examples of cardial pottery appear. Northward and westward all secure radiocarbon dates are identical to those for Iberia c. 5500 cal B.C., which indicates a rapid spread of Cardial and related cultures: 2,000 km from the gulf of Genoa to the estuary of the Mondego in probably no more than 100–200 years. This suggests a seafaring expansion by planting colonies along the coast. 
Older Neolithic cultures existed already at this time in eastern Greece and Crete, apparently having arrived from the Levant, but they appear distinct from the Cardial or Impressed Ware culture. The ceramic tradition in the central Balkans also remained distinct from that along the Adriatic coastline in both style and manufacturing techniques for almost 1,000 years from the 6th millennium BC. Early Neolithic impressed pottery is found in the Levant, and certain parts of Anatolia, including Mezraa-Teleilat, and in North Africa at Tunus-Redeyef, Tunisia. So the first Cardial settlers in the Adriatic may have come directly from the Levant. Of course it might equally well have come directly from North Africa, and impressed-pottery also appears in Egypt. Along the East Mediterranean coast Impressed Ware has been found in North Syria, Palestine and Lebanon.
- "Impressed Ware Culture". The Concise Oxford Dictionary of Archaeology. Retrieved 2008-05-11.
- "Impressed Ware". The Concise Oxford Dictionary of Archaeology. Retrieved 2008-05-11.
- William K. Barnett, Cardial pottery and the agricultural transition, in Douglas T Price (ed.), Europe's First Farmers (2000), p. 96.
- Antonio Gilman, Neolithic of Northwest Africa, Antiquity,vol 48, no. 192 (1974), pp 273-282.
- Barry Cunliffe, Europe Between the Oceans (2008), pp.115-6; Staso Forenbaher and Preston Miracle, The spread of farming in the Eastern Adriatic, Antiquity, vol. 79, no. 305 (September 2005), additional tables.
- Showcase 3 in the Archeological Museum G. A. Sanna in Sassari
- Zilhão (2001). "Radiocarbon evidence for maritime pioneer colonization at the origins of farming in west Mediterranean Europe". PNAS 98 (24): 14180–14185. doi:10.1073/pnas.241522898. PMC 61188. PMID 11707599.
- Michela Spataro, Cultural diversities: The Early Neolithic in the Adriatic region and the Central Balkans: a pottery perspective, chapter 3 in Dragos Gheorghiu (ed.), Early Farmers, Late Foragers, and Ceramic Traditions: On the Beginning of Pottery in the Near East and Europe (2009).
- Emre Guldogan, Mezraa-Teleilat settlement Impressed Ware and transferring Neolithic life style?, in Paolo Matthiae et al. (eds.), Proceedings of the 6th International Congress of the Archaeology, vol. 3 (2010), pp. 375-380.