Type 7 glasses are probably the most important group of English-made glasses of the seventeenth century. They have no recognised name, so the descriptive term 'taper stems' has been adopted. They represent the first real 'English' glass designs; introducing the simplicity of form and reliance on proportion which were to be the hall-mark of English-made drinking glass for the next century. These designs both resulted from, and exploited, the new crystal glass. They form the root for both the classic inverted-baluster stemmed and plain-stem trumpet glasses that dominated the early Georgian era and their influence can be traced into the early nineteenth century. See the classification for further details: taper stems.
Two complete glasses with tapering stems have hand-painted decoration on their bowls. Excavated and intact examples have bowls with panelled-dimple moulding, thought to be Dutch in origin and dating from after the accession of William and Mary to the English throne in 1689. Stems with wrythen moulding are also thought to date from this period.
Glasses from the later part of the period usually display one or more of the following:
Quite frequently tapering-stems have four vertical indentations to give it a quatrefoil-shaped (four-leafed clover) cross-section. Approximately the same number of glasses is known with these markings as without them.
The stems in this period are very varied, since fashion dictated rapid evolution of styles. They include stems with taper stems and extra knops or collars or similar glasses with inverted-balusters instead of the tapering stems. Some or all of these features may be wrythen or ribbed. As with the taper stems, these glasses display a marked Dutch influence. One glass is known with "God Bless King Wilijam" diamond-point engraved on the bowl. Other features include stems with type 8: quatrefoil knops and those with type 9: pincered-wing knops, sometimes called 'propeller knops'. One effect found on a number of glasses (and other groups of the same period) is a type of glass decay where the surface has a crystalline appearance, usually opaque white in colour (bright yellow has been seen!). It is possible that this is due to inadequate melting of the glass batch, perhaps linked to the introduction of covered pots in the glass furnaces.
Group 10 has multiple knops and is the fore-runner of the eighteenth-century balustroid group. See the classification for further details: type 10: multiple knop stems.
The last two types mark the start of the classic English baluster stem and the plain-stem trumpet-bowl glass. In group 11 the glasses with inverted baluster stems frequently have not yet developed the massive solid-bowl bases that are a hallmark of later glasses. Some are also truly hollow, as distinct from having a large irregular 'tear'. Group 12 plain stem glasses have developed into a recognisable plain-stem trumpet form by the mid 1690s, but usually with a bowl that is larger in proportion to the stem than their later couterparts. This reflects their development from the tapering stem glass with a round-funnel bowl.
Non-stemmed drinking glasses, such as beakers have not yet been split-up by period, but their classification can be found at beakers.