The history of Delphi’s small omphalos began with its discovery in the adyton of the Apollo Temple in 1913 and temporarily ended with its disappearance, at some point after 1951, following its denouncement as a fake. Questions had arisen earlier concerning the manner in which this artifact had been found, but most archaeologists and classicists who saw and wrote about it in the early half of the 20th century believed it to be genuine.
The omphalos was shaped using ancient tools, and its dimensions are similar to those of most omphaloi shown on bas-reliefs, coins, and ceramic wares from the Classical and Hellenistic periods. It differs, however, from other omphaloi by the presence of a narrow squarish hole, carved through it from top to bottom, and widening downwards. Holland (1933) believed that this axial tube served to funnel the “pneuma” to the Pythia during mantic sessions. Holland’s hypothesis is greatly strengthened by the recent discovery that hydrocarbon gases (including narcotic ethylene) did surface with spring waters in the adyton.