Pontil mark

The presence of such a scar indicates that a glass bottle or bowl was blown freehand, while the absence of a punt mark suggests either that the mark has been obliterated or that the work was mold-blown.

Some non-blown, free-form glass items were attached to a pontil rod in order to do finishing work on the item; such as crimping the rims, swinging the item upside down to form a swung vase etc., applying glass decorative elements, (rigaree) fire polishing the rims or re-striking, (re-heating) the items made of heat sensitive glass that changes color on the area that has been reheated.

Some glassblowers grind a hollow into the base of their work, obliterating the natural punt scar.

As commonly used in the collectibles and antiques industry, the term refers to the mark impressed on a blown glass item over this scar, since many notable glassblowers have impressed or engraved makers marks in the punt scars of their work.

[2][3] In the case of mold-blown work, where no pontil is used during manufacture, the term has also come to apply to marks impressed in the base of the work where the pontil scar would have been had it been free blown.