This article studies the discoid Didacna sp. shell beads discovered at Kaylu, a Middle Holocene burial site located in Southern Turkmenistan. Microscopic, morphometric, spectrometric, and SEM analyses were carried out on the material to identify how the beads were manufactured and used. New radiocarbon dating and bioanthropological data to age and sex the two skeletons discovered in the burials are provided. A regional synthesis shows that personal ornaments from the Caspian region were diversified through time and that a stylistic shift between the last foragers and the first farmers occurred. We also observed strong correspondences between the personal ornaments documented in the northern, eastern, and western Caspian Sea during the Neolithic, with no evidence of similar symbolic production in Northern Iran. We propose that a northern route may have allowed the diffusion of common ornamental traditions in the Caspian region to the exclusion of the southern Caspian. Alternatively, discontinuities in material culture diffusion in coastal areas could be evidence of maritime voyaging. Seafaring may have granted the fast and spatially erratic diffusion of specific bead types, people, information, knowledge, and symbols from both sides of the Caspian Sea, by long maritime voyages or by leapfrog diffusion during the Neolithic.Read less <