We conducted an identification of a substance isolated from a T‐shaped ornamental element excavated from a Globular Amphora Culture tomb at the Kowal 14 archaeological site in Poland. 14C dating indicated 4105 ± 35 bp (POZ‐21912) and 3990 ± 50 bp (POZ‐21910). Analytical methods such as SEM–EDS, XRD and FT–IR were applied to study the origin of its structure. The results of instrumental analysis and the archaeological context indicate that the adhesive substance investigated consists mainly of calcium carbonate (calcite, 78–88%), silica dioxide (quartz), sodium aluminium silicate (albite) and potassium aluminium silicate (microcline). The material might be a man‐made, mineral adhesive, a kind of lime mortar. The object is considered as the oldest European finding of this type outside the Mediterranean Basin. It provides evidence for the use of the lime calcination process in Central Europe as early as in the Late Neolithic, for which there were—up to now—no convincing premises.