The dating and identification of glassware is not always an easy task. Most glassware was never labeled or stamped with a manufacturer’s mark and it requires experience and sometimes luck to identify when and where a piece of glass was made. Indeed, it is virtually impossible to identify the majority of glassware that you are likely to find at a boot fair or flea market. Of course, if you are buying glass purely for its visual beauty then this is of little consideration. If you are collecting a particular designer or period of glass then it becomes more important.

This web page sets out to try and assist the neophyte to identify various characteristics of glassware. It is by no means comprehensive and we urge you to read up on your chosen specialisation before spending significant money. On each of our specialist web sites we try to provide more in depth information on the designers and periods we feature, and in the Links section on each site we try to provide a reading list that will help you to avoid some of the basic mistakes.

As with other forms of ceramics, the first thing to do is to look at the underside of the foot or base. Glass was hand made until fairly recently, and up until the mid-19th century was primarily hand blown using a pontil iron. A pontil iron was a thin iron bar that was attached to the foot or base of the vessel as it was being worked by the chair (the chair being the team of glassmakers who worked together to make each piece of glass). When the piece of glass was ready, the pontil iron was broken off the base, leaving a rough mark on the base of the glass.

Because of this rough mark, the feet of early glass vessels were made conical so that the roughness did not scratch the surface of the furniture on which it was sat. Pretty much all glassware made up until about 1780 will have this rough pontil mark. After that date glassware was still made with a pontil iron, which still left a rough mark, but that rough mark was more often polished out leaving a round depression in the base of the glass.

The use of the pontil iron continued up until about 1865 when it was more often replaced by a gadget which held the foot of the glassware more securely, and left its own characteristic marking – usually in the shape of a “T” but sometimes in the shape of a swirl or a “J”. The use of the pontil iron didn’t stop when the gadget came in, and some glassblowers use a pontil iron even today, leaving the mark rough or smooth as they choose. What we can be sure of though is that a piece of glass made before about 1780 must, with few exceptions,  have a rough pontil mark, and that a piece of glass made between about 1780 and about 1865 must have either a smooth or rough pontil mark. As the gadget was fairly short lived (there is not much evidence that it was used after about 1890) then we can be fairly sure that a piece of glass with a gadget mark was made in the second half of the nineteenth century.

After these dates the manufacturing processes of all but hand-blown glass left feet without recognisable markings, unless the manufacturer chose to stamp its glassware with its own maker’s mark. Normally this was done through acid etching and a number of the great glasshouses did this. These markings are sometimes very hard to see and are not always placed centrally on the foot. A good quality magnifying glass, preferably with a built-in light, is a prerequisite for trying to find these markings.