A pontil mark is the scar left on the base of a piece of hand-blown glass where the pontil rod, also called a punty, was attached during manufacture. The glassmaker fixes the iron rod to the bottom of the vessel so that the blowpipe can be removed and the rim shaped and finished; when the rod is snapped off, it leaves a rough or circular mark.
The appearance of the pontil mark varies. On earlier glass it is often left rough and sharp, while from the late eighteenth century onwards it was increasingly ground and polished away, leaving a shallow concave disc. Pressed and mould-made glass, introduced in the nineteenth century, usually has no pontil mark at all. For collectors, the pontil is therefore one of several clues used in dating drinking glasses, decanters and bottles, alongside the colour and weight of the metal, wear on the foot rim and style of decoration. A rough pontil alone does not prove early date, as reproductions sometimes imitate it, and modern studio glass may also retain one. It should always be considered together with other evidence, particularly the natural, random scratching of genuine wear.
