Part of The Grand Glossary: A Collector's Reference. This section covers the specialist vocabulary of antique glass drinking vessels, from the composition of the glass metal and the principal manufacturing techniques to the detailed classification of bowl forms, stem types, and foot forms that defines the language of English and European glass collecting. Terms are arranged alphabetically within thematic groupings.
Glass Composition and Metal
Cristallo
The clear, colourless soda-lime glass developed by Venetian glassmakers at Murano from the 15th century onwards, achieved by the careful selection and purification of raw materials and the addition of decolourising agents including manganese. Cristallo was the most prized glass of the Renaissance and early modern period, imitated across Europe by glassmakers working in the façon de Venise (Venetian manner). True Murano cristallo has a slightly grey or smoky tone and a characteristic brilliance and thinness of metal; it is distinguished from later lead crystal by its lighter weight and its different refractive index.
Façon de Venise
Glass made in the Venetian manner outside Venice itself, by Venetian emigrant glassmakers or by local craftsmen trained in Venetian techniques. The term covers a broad range of soda-lime glass produced across Northern Europe — in the Low Countries, Germany, England, France, Spain, and the Czech lands — from the 16th to the early 18th century. Façon de Venise glass encompasses the full repertoire of Venetian decorative techniques — filigrana, diamond-point engraving, enamelling, and applied hot-worked decoration — and ranges in quality from pieces virtually indistinguishable from Murano originals to crude provincial approximations.
Lead Crystal
A glass composition in which lead oxide (typically 24–30% by weight) replaces some of the lime in a standard glass batch, producing a metal of exceptional clarity, brilliance, and refractive index, with a characteristic ringing tone when struck. Lead crystal was developed in England by George Ravenscroft between 1673 and 1676, initially stabilised with lead oxide following problems with crizzling in his earlier potash-silica glass. English lead crystal rapidly superseded Venetian-style soda glass for fine tablewares and remained the dominant glass composition for English and Irish glassmaking throughout the 18th and 19th centuries. Lead crystal is heavier than soda glass, has a more brilliant surface, and cuts more crisply.
Potash Glass
A glass composition in which potassium carbonate (wood ash or potash) is used as the alkali flux in place of soda. Potash glass is harder and less fusible than soda glass and lends itself to cutting and engraving rather than hot-worked decoration. It was the standard glass composition in the German, Bohemian, and central European glassmaking tradition from the 17th century onwards, and the medium for the great tradition of Bohemian and Silesian wheel-engraved glass. Bohemian potash glass has a slightly greenish or greyish tone in early examples; the development of clear, colourless Bohemian crystal in the late 17th century produced a material that competed directly with English lead crystal.
Soda Glass
Glass in which sodium carbonate (soda ash) is used as the alkali flux, producing a relatively light, thin, workable metal suited to the hot-working techniques of the Venetian tradition — blowing, trailing, and manipulation at the furnace. Soda glass has a lower refractive index than lead crystal and does not ring when struck; it is lighter in weight and less brilliant. The majority of European glass before the development of English lead crystal and Bohemian potash crystal was made from soda-lime compositions.
Crizzling
A form of glass disease in which the surface of the glass develops a network of fine cracks and becomes cloudy, iridescent, or weeping (exuding droplets of moisture). Crizzling is caused by an imbalance in the glass composition — typically an excess of alkali or a deficiency of stabilising lime — which makes the glass chemically unstable. It was a particular problem in English glass of the 1670s, in Ravenscroft’s early experimental lead glass, and in certain Venetian and façon de Venise glasses. Mildly crizzled glass may be stable; severely crizzled glass is actively deteriorating and cannot be fully conserved. The presence of crizzling must be disclosed and significantly affects value.
Bowl Forms
Bell Bowl
A bowl form resembling an inverted bell, with a rounded base curving outward to a slightly flared rim. The bell bowl is one of the most elegant and widely used bowl forms in English drinking glasses of the early to mid-18th century, associated particularly with light baluster and balustroid stems. It is distinguished from the waisted (or thistle) bowl by its continuous outward curve and from the bucket bowl by the absence of a flat base.
Bucket Bowl
A straight-sided or very slightly tapering cylindrical bowl with a flat base, resembling a bucket in profile. The bucket bowl is found on glasses of the mid-18th century and later, including many ale glasses and rummers. It is a practical form that maximises capacity for a given height of glass.
Funnel Bowl
A bowl that widens continuously from base to rim in a straight-sided funnel shape, without a waist or pronounced curve. The funnel bowl is one of the most common bowl forms in English glasses of all periods and is found in association with virtually all stem types. A wide funnel bowl with a pronounced flare is characteristic of many early 18th-century glasses; a narrower, more upright funnel is associated with later periods.
Ogee Bowl
A bowl with an S-shaped profile in cross-section, curving inward at the base and outward above the waist to produce a characteristically elegant double-curve. The ogee bowl is associated with the rococo taste of the mid-18th century and is found on glasses with plain, opaque-twist, and mixed-twist stems. The quality of the ogee curve — the fluidity and precision of the double bend — varies considerably between examples.
Round Funnel Bowl
A bowl with a rounded lower portion curving into a straight or slightly flared upper section, combining the depth of the bell form with the openness of the funnel. The round funnel is a common bowl form in English glasses of the mid-18th century and is found on a wide range of stem types.
Thistle Bowl
A bowl form with a rounded, often generous lower portion narrowing to a pronounced waist before flaring again to the rim, resembling the profile of a thistle flower. The thistle bowl is particularly associated with Irish glass of the late 18th and early 19th centuries and with certain types of heavy cut glass. It is also found in earlier English glasses, where it is sometimes called a waisted bowl.
Trumpet Bowl
A bowl that flares dramatically from a narrow base to a wide, open rim in a continuous trumpet-like curve, without a waist. The trumpet bowl is one of the most characteristic forms of the English baluster period (c.1685–1725) and of the later plain-stem period, used for wine glasses, champagne flutes, and cordials. The proportions of the trumpet — the degree of flare, the height relative to the stem — vary considerably and are an important element of the aesthetic assessment of a glass.
Stem Types
Air Twist Stem
A stem type in which one or more columns of air bubbles, drawn out into a continuous spiral by the twisting of the hot glass, are enclosed within the stem. Air twist stems were produced in England from approximately 1740 to 1770 and represent one of the most admired achievements of the English glassmaker’s art. The twist is formed by introducing one or more air bubbles into the gather of glass and then drawing and twisting the stem as it is worked. Air twists are classified by the number and arrangement of the spiral elements: a single spiral thread, a double series, a multiple spiral gauze (in which many fine threads form a gauze-like structure), and a corkscrew are among the principal types. The quality of the twist — its regularity, the fineness of the threads, and the consistency of the spiral — is the primary indicator of quality.
Baluster Stem
A stem type characteristic of English glasses of the period c.1685–1725, formed by one or more knops (swellings) of various forms on a drawn stem, often with a pronounced base knop above the foot. The heavy English baluster glass of this period — with its generous lead-crystal metal, its bold stem elements, and its restrained decoration — is among the most collected of all English glass types. Baluster stem elements include the true baluster (an elongated pear-shaped swelling), the inverted baluster, the acorn knop, the angular knop, the cushion knop, the drop knop, the annulated knop (with encircling rings), and others. The vocabulary of baluster stem elements is precise and must be applied carefully.
Balustroid Stem
A lighter, more attenuated version of the baluster stem, characteristic of the period c.1725–1750, in which the stem elements are less massive and the glass metal somewhat lighter than in the true baluster period. The transition from heavy baluster to lighter balustroid reflects changing taste and the influence of continental styles. Balustroid glasses typically have more elongated proportions and a greater variety of stem combinations than the earlier baluster glasses.
Composite Stem
A stem combining elements from more than one stem type in a single glass — for example, an opaque twist section combined with an air twist section, or a plain section combined with a knop and a twist. Composite stems are found throughout the 18th century and are sometimes the result of deliberate design, sometimes of the reuse of stem elements from different glassmaking operations.
Faceted Stem
A stem decorated with flat-cut facets — typically diamond, hexagonal, or scale patterns — ground and polished onto the surface of the glass after annealing. Faceted stems are characteristic of the neo-classical period (c.1760–1800) and reflect the influence of Bohemian cut glass on English taste. The quality of the cutting — the sharpness of the facets, the regularity of the pattern, and the quality of the polishing — varies considerably.
Mixed Twist Stem
A stem combining both air twist and opaque (enamel) twist elements within the same stem, either in distinct sections or interlaced with each other. Mixed twists are among the rarest and most technically demanding of all English twist stem types and are correspondingly sought by collectors. The combination of the bright white of the enamel threads and the glittering air bubbles of the air twist creates a particularly rich and complex visual effect.
Moulded Pedestal Stem (Silesian Stem)
A stem formed by moulding the hot glass in a ribbed or faceted mould to produce a shouldered, pedestal-like form with a moulded pattern on its surface. The shouldered pedestal stem — sometimes called the Silesian stem, though its precise origin is debated — was fashionable in England from approximately 1715 to 1765 and is found on glasses of considerable quality. The moulded pattern is typically four-sided or six-sided, with ribs, diamonds, or other geometric motifs.
Opaque Twist Stem (Cotton Twist)
A stem type in which one or more columns of white (or coloured) enamel glass, drawn out into a spiral, are enclosed within the stem. Opaque twist stems were produced in England from approximately 1745 to 1780 and are the most numerous of all English twist stem types. The white enamel threads are formed from opacified glass (made opaque by the addition of tin oxide or arsenic) and have a distinctive chalky white appearance. Opaque twists are classified by the number, arrangement, and form of the enamel elements: a single thread, a pair of threads, a multiple spiral, a corkscrew, a lace twist, a gauze, and many other configurations are recorded. Coloured twist stems — in which one or more of the threads is blue, green, red, or another colour — are rarer and more sought than white twists.
Plain Stem
A stem without knops, twists, or other decorative elaboration, drawn directly from the base of the bowl as a simple cylinder or slight taper. Plain-stemmed glasses were produced throughout the 18th century and represent a significant proportion of surviving English drinking glasses. They are not without interest or quality: the proportions of the plain stem, the quality of the metal, and the form of the bowl and foot combine to produce glasses of great elegance in the best examples.
Foot Forms
Conical Foot
A foot that slopes upward from the outer edge to the centre, forming a cone shape. The conical foot is the standard foot form for English glasses of the baluster and later periods and is found in association with virtually all stem types. The angle of the cone varies: a steep, high-domed conical foot is characteristic of early glasses; a flatter, more spread foot is more common in later examples. The quality of the foot — its weight, its diameter relative to the bowl, and the neatness of the pontil mark at its centre — contributes significantly to the overall aesthetic of the glass.
Domed Foot
A foot with a pronounced dome rising from the outer edge to the centre, higher and more emphatic than the standard conical foot. Domed feet are associated with the heavy baluster period and with certain later glass types; a domed and folded foot (in which the outer edge of the dome is folded under) is a particular feature of early high-quality glasses and provides additional strength at the vulnerable outer rim.
Folded Foot
A foot in which the outer edge of the glass is folded under (doubled back on itself) to create a reinforced rim. The folded foot is found on English glasses from the late 17th century to approximately 1750–60, after which it becomes less common, probably because the improvement in annealing techniques reduced the need for this reinforcement. The presence of a folded foot is an indicator of earlier manufacture and is valued by collectors as evidence of age and quality.
Plain Foot
A flat or slightly domed foot without folding or other elaboration, the standard foot form for English glasses from the mid-18th century onwards. The quality of the plain foot is assessed by its weight and thickness (heavier feet indicate better quality glass), its diameter relative to the bowl (well-proportioned feet give the glass stability and visual balance), and the neatness of the pontil scar.
Pontil Mark
The scar left on the base of the foot by the pontil (punty) rod — a solid iron rod attached to the base of the glass after it is removed from the blowing iron, to allow the glassmaker to finish and fire-polish the rim. When the pontil is detached, it leaves a rough, circular scar on the centre of the foot. On early glasses, the pontil mark is left rough or only lightly smoothed; on later glasses it may be ground flat or polished. The form of the pontil mark — its size, depth, and finish — is a useful indicator of date and quality.
Terraced Foot
A foot with a stepped or terraced profile, in which the foot rises in two or more distinct levels from the outer rim to the centre. Terraced feet are found on certain heavy baluster glasses and on some ratafia and cordial glasses; they are a relatively rare foot form and their presence is noted in detailed descriptions.
Decorative Techniques
Cutting
The decoration of glass by grinding facets, mitre cuts, prisms, and other geometric patterns into the surface using iron or stone wheels fed with an abrasive slurry, followed by polishing on wooden or cork wheels. Cutting exploits the high refractive index of lead crystal to create a brilliant, light-diffracting surface. English and Irish cutting of the late 18th and early 19th centuries — particularly the deep relief cutting associated with the Irish glass houses of Waterford, Cork, and Belfast — is among the most spectacular and widely collected of all glass decoration. Cut patterns include flat cutting, step cutting, relief (or pillar) cutting, diamond cutting (flat and hobnail), fan cutting, and combinations thereof.
Diamond-Point Engraving
The scratching of a design into the surface of glass using a diamond or hardened steel point, producing a fine, scratched line. Diamond-point engraving was the dominant form of glass decoration in the Venetian and façon de Venise tradition and in the Netherlands from the 16th to the 18th century. Dutch diamond-point engraving of the 17th century — particularly the calligraphic work of Anna Roemers Visscher and Maria Tesselschade, and the stipple work of Frans Greenwood and David Wolff — represents the highest achievement of the technique. Diamond-point engraving leaves a fine, bright line in contrast to the broader, deeper marks of wheel engraving.
Enamelling
The decoration of glass with vitreous (glassy) colours applied to the surface and fused by firing in a muffle kiln at low temperature. Enamelling on glass was practised in the Venetian tradition from the 15th century and was used across Europe for armorial decoration, commemorative inscriptions, and pictorial ornament. In England, Michael Edkins of Bristol decorated opaque white glass with enamel colours in the Chinese taste; the Beilby family of Newcastle applied enamel decoration — including elaborate rococo borders, armorials, and pastoral scenes — to English lead crystal glasses of the mid-18th century. Beilby enamelled glasses are among the most sought by collectors of English glass.
Gilding
The application of gold to the surface of glass, either as gold leaf or as a gold-mercury amalgam (honey gilding), fired and burnished. Gilding was used for borders, inscriptions, and decorative motifs on English and continental glass. It is fragile and wears with use and washing; surviving gilding in good condition, bright and unfaded, is more desirable than worn or partially lost gilding. The gilding on Bohemian Zwischengoldglas (gold sandwich glass, in which gold leaf is engraved and sandwiched between two layers of glass) is protected from wear and survives in excellent condition.
Wheel Engraving
The decoration of glass by holding it against a rotating copper, stone, or rubber wheel fed with an abrasive, cutting into the surface to produce a design in intaglio. Wheel engraving allows for much greater detail and tonal range than diamond-point engraving and is the medium of the great Bohemian and Silesian engraving tradition. In England, wheel engraving was used for armorial decoration, commemorative inscriptions, and naturalistic ornament from the late 17th century. Distinguished English engravers include William and Mary Beilby (who also worked in enamel) and the later craftsmen of the Stourbridge district. The quality of wheel engraving is assessed by the precision of the cutting, the range of depth and texture achieved, and the naturalism of figurative work.
Principal Glass Types
Ale Glass
A tall, slender glass for serving ale or beer, typically with a deep, narrow bowl — most commonly a round funnel or bucket form — on a plain or air-twist stem. Ale glasses are often decorated with engraved hops and barley, the heraldic symbols of the brewer’s trade. The engraving of hops and barley is one of the most common forms of wheel-engraved decoration on English drinking glasses and is found on glasses of all qualities.
Cordial Glass
A small glass for serving cordial or liqueur, with a small bowl — typically a trumpet, round funnel, or ogee form — on a relatively tall stem. Cordial glasses are among the most delicate and refined of all English glass types and are found with all the major stem forms of the 18th century. Their small size means that condition is particularly important: any chip, crack, or repair to the bowl or rim is correspondingly more significant than on a larger glass.
Jacobite Glass
A drinking glass engraved with Jacobite symbols — the rose and buds (representing the Stuart claim to the throne of England and Scotland), the thistle, the portrait of the Young Pretender (Charles Edward Stuart), mottoes including Fiat (let it be done) and Redeat (let him return), and other emblems — used by supporters of the Stuart cause during the period c.1720–1760. Jacobite glasses are among the most intensely collected of all English glass types; their identification requires careful attention to the specific symbols and mottoes present. A large body of later reproductions and fakes exists, and genuine Jacobite glasses must be distinguished from later copies by the quality of the engraving, the form of the glass, and the character of the metal.
Ratafia Glass
A tall, slender glass with a very narrow, elongated bowl for serving ratafia (a sweet liqueur or cordial), produced in England in the mid-to-late 18th century. The ratafia glass is one of the most elegant and delicate of all English glass forms; its narrow bowl and tall stem require great skill to produce and make it correspondingly vulnerable to damage. Complete, undamaged ratafia glasses in fine condition are relatively rare.
Rummer
A short-stemmed, large-bowled drinking glass produced in England from the late 18th century onwards, used for spirits mixed with water (particularly rum and water, from which the name may derive, though the etymology is disputed). Rummers typically have bucket or ogee bowls, short plain or knopped stems, and heavy plain or square lemon-squeezer feet. They were produced in large quantities in the late Georgian and early Victorian periods and are frequently engraved with initials, toasts, views of buildings, and commemorative inscriptions. The engraving on rummers ranges from crude scratched work to fine wheel engraving of considerable quality.
Toastmaster’s Glass
A glass with a deceptively small bowl disguised within a larger apparent bowl, designed for use by the toastmaster at formal dinners, who was required to propose many toasts but needed to remain sober. The thick walls of the inner bowl reduce the capacity of the glass to a fraction of its apparent volume. Toastmaster’s glasses are a recognised collecting category and are identified by the disproportionate thickness of their bowl walls relative to the apparent volume.
Condition and Assessment
Chips and Rim Damage
Small chips to the rim of a drinking glass are the most common form of damage and the most significant in their effect on value, as the rim is the most vulnerable point of the glass and chips are both unsightly and potentially dangerous in use. A chipped rim may be professionally ground down and repolished, reducing the height of the glass; such repairs should always be disclosed and are detectable by measurement against recorded heights of the type and by examination of the rim profile. Even a fine, polished chip reduces value significantly.
Cloudiness and Iridescence
A milky or iridescent film on the interior or exterior surface of a glass, caused by the leaching of alkalis from the glass by water or acid, or by the early stages of crizzling. Mild surface cloudiness may sometimes be reduced by careful cleaning; iridescence caused by burial or long storage in damp conditions is stable but permanent. The extent and distribution of cloudiness or iridescence must be assessed in the light and disclosed in descriptions.
Firing Crack
A crack in a glass vessel that occurred during manufacture or annealing, typically running through the wall of the bowl or foot in an irregular pattern. Firing cracks are present from the time the glass left the factory and are part of its production history; they are generally considered less serious than post-manufacture damage but weaken the glass structurally. They must be disclosed.
Star Crack
A radiating pattern of cracks emanating from a central point of impact on the base or foot of a glass, typically caused by a sharp blow. Star cracks are a form of impact damage and reduce value in proportion to their extent and visibility. A small, contained star crack on the foot of a glass of otherwise outstanding quality may be acceptable to many collectors; a star crack on the bowl is more serious.
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