Sotheby's Glass Glossary

Glossary Center

Glossary from the back of Sotheby’s Concise Encyclopedia of Glass  biblio 
Provided here under fair use of copyright
Not completely proofed, especially foreign language names.
Rev. 2008-04-05 add alphabetical links

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A
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abrading
Technique of grinding shallow patterns into a glass surface with a wheel.
acid-etching
Technique developed in the 18th century to give glass a satin matt, shiny or frosted finish by exposing it to hydrofluoric acid. Areas not to be etched were covered by an acid-resistant protective layer (wax, varnish or oil) into which a design was scratched before the acid was applied. Also used on cameo glass to remove areas of the overlay.
agate glass
See calcedonio
air-twist
See twist.
alabaster glass
Type of translucent glass, usually white, first developed in Bohemia in the Biedermeier period. Frederick Carder produced iridescent alabaster glass at Steuben. See lattimo and opal.
alabastron
Small, cylindrical perfume flask of ancient Greece, made in core-formed glass, with a rounded base, broad rim and two small side handles.
albarello
Italian; waisted, cylindrical jar, more usually made in tin-glazed earthenware, for holding medicines.
Aldrevandin Group
Group of Medieval enamelled glass beakers made toward the end of the 13th century, their place of manufacture in doubt; named after an example in the British Museum inscribed 'magistkr aldrevandin me FECI(T).
alkali
Essential ingredient in making glass, added to the batch in the form of potash (to make Waldglas) or soda (from barilla) to reduce the temperature at which the silica (in the form of sand and occasionally flint) would fuse.
Almorratxa
X or almorrata Spanish; type of sprinkler with many spouts for containing rose-water.
Amen glass
Type of English glassware used for toasting the Jacobite cause (particularly the Old Pretender, James Stuart), decorated with verses of the Jacobite Hymn ending with the word 'Amen' and a crown executed in diamond-point,
usually on a drawn-stem wine glass.
amphoriskos
Small perfume jar of ancient Greece, sometimes made in core-formed glass, with a shouldered body, pointed base and two handles; a miniature amphora used for oil and wine.
amulet
Glass ornament worn from Egyptian times to ward off evil.
Annagelb
German; see uranium glass.
Annagriin
German; see uranium glass.
annealing
Process through which all glass vessels pass, wherein the finished hot object is cooled very slowly and evenly in an annealing oven to reduce any internal stresses that might have built up during its manufacture that would otherwise cause it to crack once cold.
art glass
1. Term applied to ornamental rather than functional glassware. 2. Types of American glassware dating from the 1890s onward, such as Aurene glass.
Aryballos
Small globular bottle of ancient Greece, with two handles for suspension, made in core-formed glass; for cosmetic oils and balms.
Aurene glass
Type of American art glass developed by Frederick Carder, its metallic surface obtained by spraying the glass with metallic chloride solutions through a flame.
aventurine
Translucent glass with glittering metallic inclusions made in imitation of aventurine quartz; flakes of gold were used in i 5th-century Venetian glass, copper from the 17th century.
B
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balsamarium
Small container of ancient Greece and Rome, usually a bottle; for perfumed oils, cosmetics or balms.
baluster
Type of drinking glass, its stem in the form of a baluster (adopted from Renaissance architecture), which could be inverted or decorated with knops, internal tears and bubbles
Baluster glass
balustroid
Type of baluster glass but with a lighter, more elongated stem. Although sometimes called 'Newcastle light balusters', they are now thought to have been produced mainly in Holland. (Above)
barilla
(Salsola soda), salt-water marsh plant, the ashes of which were used as the alkali in making glass.
Baroque
From the Italian barocco, a late Renaissance style dating from c.166o. Its exaggerated movement is reflected in the stem formations of Venetian glass and in German glass as Laub und Bandelwerk.
basket
1. Glass in the shape of a basket, sometimes with an overhead handle. 2. Type of paperweight with a funnel-shaped lattice support, usually holding fruit and flowers.
batch
Mixture of raw ingredients (generally alkali, lime and silica) that are melted and fused together in a pot or crucible to make glass. To this was added a proportion of broken glass, or cutlet, and metal oxide colorants.
Berkemeyer
German; 16th-and 17th-century Waldslas drinking glass, with a cylindrical lower part decorated with prunts and a flaring bowl.
bevelled
Type of flat glass with a sloping edge to protect it from chipping, usually found on the edges of mirrors.
Biedermeier
German, 'honest fellow'. The bourgeois style current in German decorative arts from (".1825 to 1840. In glass it takes the form of a change away from colorless to colored glass (including Hyalith, Lithyalin and uranium glass), and flashed glass.
blank
Any preliminary shape of a glass object that requires further forming or finishing processes.
Blankschnitt
German, 'polished cut'. Style of engraved decoration, attributed to Georg Schwanhardt, found on German potash glass, particularly from Nuremberg, in which the relief effect is enhanced by polishing the ground part of the intaglio.
blowing
Technique of shaping a molten mass of glass by blowing air into it through a blowpipe, either freehand or into a mold of two or more parts. It was first developed in the latter part of the 1st century BC.
blowpipe
Hollow metal tube, about 1.5m (5ft) long and 2cm (3/4in) in diameter, with a mouthpiece at one end and a thin ring fitted to the other that helps to retain the gather of molten glass from the pot. Air is blown through the mouthpiece to inflate and form the glass.
boracic
Type of glass produced bv Clichy in 1849 using borax, which, in the form of boric acid, was added to the batch as a flux in making lead glass. It was claimed to be free from bubbles and other impurities, and strong, being resistant to chips and changes in temperature.
brilliant cut
Style of cut glass with very deep and highly polished complex cuts; developed in the United States during the second half of the 19th century.

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C
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cage cup
Type of thick-walled late Roman glass that was undercut with an intricate openwork or figural pattern attached to the main body of the vessel by small hidden bridges. See Lycurgus Cup.
calcedonio
Italian; marbled glass (with brown, blue, green and yellow swirls) made in imitation of banded semiprecious stones; originally made in Venice from the late 15th century and revived in the second half of the 19th century. Also known as agate and chalcedony glass.
came
Grooved slip of lead securing glass in leaded- and stained-glass windows.
cameo
Decorative cased or flashed glass with two or more different colored layers, the outer layer(s) cut away so that tile design stands out in relief against the background color. First developed by the Romans from techniques used for banded stone and shell cameos at the end of the 1st century BC and revived in the 19th century. See also Portland Vase,
cane
Slender, patterned rod formed by fusing together groups of colored rods which, while still molten, were pulled out to reduce their diameter and to produce an internal polychrome design. Once cold, slices were cut, either to make millefiori and mosaic glass, or to incorporate into stems of drinking glasses. See twist.
casing
Technique of forming two or more layers of glass to make cameo glass. A hollow blank of the outer layer is made before a gob of the inner background is blown inside it. The two then fuse as they are inflated together. Also used in paperweights, where the opaque colored outer layer is cut away to form 'windows' through which the design can be seen.
cast glass
Made from the 8th century BC by fusing powdered frit in single or interlocking molds.
chalcedony
See calcedonio.
cinerary urn
Large container, sometimes lidded, with a spherical or ovoid body and a broad rim, used at first for storage purposes and later, from the 1st to mid 3rd centuries AD, as burial urns for ashes.
claw-beaker
Tall Merovingian beaker, dating from the 5th to 8th centuries, with a body tapering toward a narrow foot and decorated with several rows of hollow, claw-like prunts. Called Russelhecher in German.
Clichy rose
Cane made at Clichy resembling an open rose, with a pink central cylindrical motif surrounded by fLmened tubes of green glass. Used in millefiori paperweights.
collar
Circular ring of glass used at the junction of bowl to stem or between stem and foot on some wine glasses.
color band
Early Roman glass combining the techniques of casting and blowing, wherein globular bottles arc formed from mosaic canes that were gathered on a blowpipe and inflated.
concentric
Type of millefiori paperweight
in which florets (slices from large canes) are arranged in concentric circles.
core-formed glass
Type of glass dating from 1500 BC (before the invention of blowing), whose method of manufacture involves shaping trails of molten glass over a core of mud or clay (sometimes supported by a metal rod) and fusing them together in the furnace. After annealing the core was scraped out. Made in the form of alabastra, amphoriskoi, aryballoi and other vessels.
cristallo
Italian; type of soda glass made with the ashes of barilla, which, with the addition of manganese oxide, produced a colorless glass that resembles rock crystal. First developed in Venice in the 15th century. See also crystal.
crizzling or crisselling
Defect in glass caused by an imbalance in the batch, usually an excess of alkali, which makes the glass deteriorate; characterized by an internal network of fine cracks and sometimes surface dampness. It was corrected by George Ravenscroft in his development of lead glass in c.\6'j6.
crown technique
Technique for producing sheet glass wherein a bubble of blown glass was cut open, rotated rapidly and reheated frequently until it formed a flat disc attached to the end of the pontil rod. After annealing the glass could be cut to various sizes.
crown weight
Hollow paperweight, made at St Louis, in which a pattern of twisted ribbons is arranged vertically and drawn together at the top.
crystal
Colorless, transparent glass that resembles rock crystal. The word is derived from the Greek word for rock crystal, krystallos, or 'clear ice'. The term is now generally applied to high-quality cut glass. See also cristallo and lead glass.
cullet
Fragments of raw or broken glass melted down with the new ingredients of a batch to act as a flux to reduce the time required to make glass. More here
cutting
Decorative technique, employed since pre-Roman times, in which glass is ground away from an object's surface by a rotating wheel fed with water.
cylinder technique
Technique for making flat or 'broad' glass for mirrors or windows. A large, elongated glass bubble is blown and then removed from the blowpipe so that both ends can be cut to produce a cylinder. This cylinder is slit lengthwise with shears [MF error: scored with cutter or hot rod while cold] and placed in a furnace, where the two sides uncurl (through mechanical force or gravity) to form a flat sheet of glass. [alternate Broad]
D
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Daumenglas
German, 'thumb glass'. Large cylindrical or barrel-shaped Waldglas beaker with circular indentations for the fingers and thumbs to grasp while drinking from it.
decanter
Decorative bottle with stopper used for serving wine, spirits and even ale. The many shapes include bell, claret, club-shaped, cruciform, magnum, mallet, onion-shaped, Rodney, shaft and globe, ship's, shouldered, stirrup and whisky.
decanter jug
Type of jug with a handle and stopper used as a decanter
diamond air-trap
Decoration wherein air pockets embedded in the glass are arranged in a diamond-shaped pattern; patented by W.H., B. &J. Richardson in 1857. A gather of glass is blown into a mold with projections of the desired design and covered by another parison so that the indentations trap air pockets.
diamond-cutting
Decorative cut patterns: plain, strawberry or hobnail.
diamond or diamond-point engraving
Linear drawing on a glass surface by means of a diamond or metal point, used since the second quarter of the 16th century across Europe. Later the technique of stippling with a diamond-point was developed.
diatretarius
Latin; Roman glass-cutter or glass decorator, as opposed to vitrearius, glass-maker or glass-blower.
diatretum
See cage cup.
dichroic
Showing different colors when viewed in transmitted or reflected light. Achieved by adding metal to the batch, originally gold, later uranium or copper oxide, in a reducing atmosphere. See Lycurgus Cup.
dip-molding
Technique using a one-piece mold to achieve a pattern that can be further expanded on the blowpipe.
double ogee bowl
Type of wine-glass bowl with a profile of two connected 'S's.
dromedary flask
Type of post-Roman glass flask, found in Syria from the 6th to 8th centuries AD, decorated with heavy openwork trailing and shaped to resemble a dromedary.
E
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enameling
Decorative technique wherein colored powdered glass, mixed with an oily medium, is painted on to the glass surface and then reheated in the furnace to fuse the design. Practised since the 1st century AD.
engraving
Technique of cutting into the surface of a glass by holding against the glass a rotating wheel of stone or metal fed with an abrasive.

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F
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faceting
Technique of decorating curved glass surfaces by grinding to make shal­low depressions that are flat or nearly so.
façion de Venise
French, 'in the Venetian style'- Term used to describe high-quality glassware of Venetian influence, as opposed to forest glass or Waldglas, made throughout Europe in the 16th and 17th centuries.
faience
Porous body of finely ground quartz (a form of silica) held together by a glassy 'connective tissue' and covered with a colored vitreous glaze. It can be modeled or thrown on a wheel to achieve its final shape before being fired.
filigrana
Italian, 'thread grained'. Type of glass originally made in Murano in the second quarter of the 16th century. Term covers all styles of decoration in which threads of glass (usually opaque white) are embedded in clear glass to form a very fine network pattern. The terms latticinio or latticino are also used. These designs include vetro ajili, vetro a reticello and vetro a retortoli. See also filigree.
filigree
English term for filigrana, wherein a rod incorporating thin white or colored threads is manipulated to give the appearance of lace.
flashing
Technique of applying a thin glass layer of a contrasting color to a glass object by dipping it into a pot of molten metal that can be cut away to leave a design in cameo.
flint glass
Misused term for lead glass, wherein the silica is obtained from powdered flints (impure quartz) rather than from sand.
flute
Very tall and slender flaring wine glass on a short stem.
flute
cutting Pattern of parallel grooves on cut glass occurring in a variety of forms: mitred ("V'-shaped), round (concave semi-circular) and hollow (concave semi-elliptical).
flux
Alkaline substance that is an essential ingredient in the batch to aid the fusion of the silica, added as potash or soda.
forest glass
English term for glass with a strong greenish tint in which the alkali or flux in the batch is obtained from the ashes of burnt wood or ferns. The green is caused by iron alloys from the impure potash. Called Waldglas in German.
frit
Term referring to some of the ingredients of glass that are pre-heated until they are red-hot but not fused; these are then cooled and ground into a powder and added to the other ingredients of the batch. This process removes moisture from the material and the gases that might result when heated, thus producing glass with fewer impurities.
G
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gadrooning
Continuous decorative pattern of short sections of ribbing either molded, applied or deep cut; inspired by patterns on late 17th-century silver.
gaffer
The head glass-maker, sometimes called a master blower, who does the most skilled work.
gather
Blob or mass of molten glass attached to the end of a blowpipe or pontil before an object is formed from it.
gilding
Technique of decoration wherein the surface or back of a glass vessel is covered with gold leaf, gold paint or gold dust mixed with a fixative and then fired. Alternatively, the gilding can be engraved with a design, cold-painted or sandwiched between another layer of glass (gold sandwich). See also Zwischengoldglas.
glass
Homogeneous material which has a random, liquid-like (non-crystalline) molecular structure.
Glasschneider
German, 'glass-cutter'.
gold-band glass
Type of ancient mosaic glass with serpentine lengths of pre-formed canes of blue, purple, green and gold-sandwich glass.
gold-sandwich glass
See gilding and Zwischengoldglas.
Graal glass
Trade name for colored mosaic-like glass developed by Orrefors in Sweden in 1916. [Graal]
grisaille
1. Decorative painting in shades of grey on glass, sometimes used to imitate relief sculpture. 2. Brownish paint made from iron oxide, fused on to glass to define details in stained-glass windows.
H
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hand cooler
Small, egg-shaped glass object used either as a darning egg or to cool the palms of a lady's hand.
Hausmaler
German, 'home painter'. A freelance or independent painter who decorated glass direct from the factory during the 17th and 18th centuries.
Hedwig beaker
Type of thick-walled glass beaker of the 11th or 12th century, cut in high relief with stylized lions, griffins, eagles or palm-leaf patterns. Named after St Hedwig (d. 1243), because one of the surviving examples supposedly belonged to her.
Hochschnitt
German, 'high engraving'. Technique of cutting glass in which the design stands out in high relief from the vessel body; opposite of intaglio.
Hofglasschneider
German, 'court glass-cutter'. Highly skilled glass-cutter attached to a German court, especially in the 18th century.
Hofkristalschneider
German, 'court crystal cutter'. As for Hofglasschneider.
Humpen
German; tall, cylindrical beer or wine beaker made of Valdglas from the mid 16th to the 18th centuries.
huqqa
Indian, 'hookah'. Globular or bell-shaped bottle, to which a long flexible tube for smoking tobacco is attached.
Hyalith
Opaque black and, more rarely, opaque red glass in imitation of Wedgwood's basaltes ware, made in Bohemia from 1817 by the glasshouse of Count von Buquoy.
Ice Glass vase
I
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ice glass
Decorative glassware with an outer surface resembling cracked ice, first produced in Venice during the 16th century. Made principally by plunging the hot glass briefly into water and then reheating it, or by rolling the hot glass over splinters and fragments of glass laid out on a marver and then reheating it to fuse the pieces to the surface. (Above)
incrustation
Technique of inserting non-glassy matter, commonly ceramic, into glass, introduced in the last third of the 18th century. These encrusted pieces, also known as 'crystallo ceramic' and sulphides, were used in paperweights, pendants, decanters and jewel boxes.
inlay
Any small, flat piece of glass fastened on to the surface of a larger object and cemented into place to form a component of a larger decorative design.
intaglio
Technique of engraving or wheel-cutting a design below the surface of a glass object, in order to produce an image in relief whose background is in the highest plane; therefore, the opposite of Hochschnitt.
Intarsia glass
A type of art glass, introduced by Frederick Carder, which has a layer of colored glass with an etched design sandwiched between two colorless layers.
iridescence
Rainbow-like effect found on the surface of excavated glass objects caused by a chemical attack on the surface of the glass resulting from its environment. This effect was artificially reproduced in Art Nouveau glass by the application of a metallic lustre.

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J
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Jacobite glass
English glassware principally engraved (or, rarely, enamelled) with portraits, emblems (rose, star or thistle) or inscriptions ('Fiat', or 'Let it be done'; 'Redeat', or 'May he return') and verses from the Jacobite anthem — see Amen glass — to commemorate the Stuart cause of the Old and the Young Pretenders (James Stuart and Charles Stuart, or 'Bonnie Prince Charlie')/
jelly glass
Small vessel, usually of inverted conical or bell form on a flat foot, used for custards, jellies or syllabubs-kick Conical indentation in the base of a glass vessel formed by the pontil rod, ranging from a slight concavity to a deep, conical hollow, to add stability and to collect sediment from the liquid inside.
K
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knop
Decorative blob or bulge on the stem of a glass; can be hollow or solid and comes in a variety of shapes, including acorn, annular, ball, bobbin, cylinder, drop, egg, flattened, melon, multiple, mushroom and winged-
Krautstrunk
German, 'cabbage stalk'-Type of beaker, decorated with large flat prunts, made in Waldglas during the 15th and 16th centuries.
Kugler
German; glass-cutter in the 18th and early 19th centuries who specialized in circular and oval cutting and other techniques in the Biedermeier style.
Kunckel red
Type of glass colored ruby red through the addition of gold chloride to the batch. Developed by the chemist Johann Kunckel, probably before 1679. Called Rubinglas, or Goldrubinglas, in German.
L
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lacy glass
1. See filigree. 2. Type of American pressed glass in which the decoration of flowers or foliage is set against a diaper background, giving an overall sparkling lacy effect.
lampwork
Glass either blown or manipulated from clear or colored glass rods over a torch or blow lamp, used in paperweights and Nevers figures.
lathe-cutting
Technique whereby blanks of glass are mounted and turned slowly with the aid of a bow or handled wheel while a tool fed with an abrasive is held against the glass in order to cut sharp profiles or to polish the overall surface.
lattichinio or latticino
Italian, from the word fatte, 'milk'. Clear glass decorated with embedded threads of white glass to form network patterns- See filigrana-
lattimo
Italian, from the word latte, 'milk'- Opaque white glass colored by adding bone ash or tin oxide to the batch and sometimes by adding antimony or zinc. Known as Milchglas in German.
Laub und Bandelwerk
German, 'leaf and strapwork'. Term for a Baroque decorative pattern of intricate intertwined leaf and floral motifs.
lead glass
Type of glass containing a large amount of lead oxide (24-30%), first made by George Ravenscroft as a remedy for crizzling. The resulting glass is more brilliant than cristallo and softer and better suited for cutting.
Linen Smoother
linen smoother
Glass object with a heavy flat, rounded base and a handle used as a pressing iron. (Above)
Lithyalin
Type of glass, invented by Friedrich Egermann, which is opaque (usually red) and marbled on the surface in imitation of semiprecious stones.
lustre painting
Technique of producing an iridescent effect on the surface of glass by using metallic pigments that are fired in a reducing atmosphere.
Lycurgus Cup
A cage cup of dichroic glass (opaque pea green in reflected light and red in transmitted light) made in the 4th century AD; cut with figures from the myth of King Lycurgus.
M
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marbled
Type of glass decorated with different colored streaks resembling the patterns in marble.
marver
Flat iron (probably originally marble) table upon which the gather is rolled into an evenly shaped mass.
marvering
Technique of rolling hot, softened glass over a flat surface (a marver) in order to smooth out the vessel, to consolidate trailed decoration applied to the vessel or to pick up decoration in the form of blobs or fragments of glass.
matrix
Mass of glass that encloses mosaic glass.
Matsu-no-ke glass
Japanese-influenced design developed by Frederick Carder and registered by Stevens & Williams in 1884. Term also covers a Japanese style of decoration used in the latter part of the Victorian period
Merese collar on goblet
merese
Type of collar like a flattened knop, with a sharp edge generally applied to the stem, often in the form of a joint between the bowl and the stem. (Above)
metal
Term describing glass while molten or cold, used to distinguish the material from the object.
Milchglas
German, 'milk glass'.See Ultimo.
millefiori
Italian, 'a thousand flowers'. Term used to describe mosaic glass used in ancient and Venetian glass as well as in paperweights.
mosaic
Pre-formed, sliced canes of glass placed around or in a mold, heated slowly until the elements fuse together to form the required shape and then polished when cold to smooth the surface.
mosque lamp
Hanging lamp with bulbous body, flaring mouth and thick loop handles for suspension from mosque ceilings. First made in Syria in the 13th and 14th centuries, they were decorated in gilding and enamel, often with inscriptions from the Koran.
Moss Agate glass
Type of art glass developed by John Northwood and Frederick Carder in the late 188os. A gather of soda glass was cased in lead glass, coated in powdered colored glass and again cased in lead glass, which was injected with water to cause the weaker soda glass to crack. After the water was emptied out it was reheated to leave a crackled network.
mold-blowing
Technique of blowing a gather of glass, while attached to a blowpipe, into a wooden or iron mold in two or more parts; the decoration on the inside can be further inflated to reduce the sharpness of the design.
molded pedestal stem
Type of molded stem that is ribbed and shouldered with generally between four and eight sides; made in England and Germany and popular from ^".1715 to 1765. Sometimes called Silesian stems.
mold-pressing
Technique of forcing or pressing hot glass into an open or multiple-part mold.

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N
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Nef
Table ornament in the shape of a rigged sailing ship.
Neoclassicism
Style from the latter part of the 18th century based on a renewed interest in the arts of Greece and Rome; largely inspired by the excavations at Pompeii and Herculaneum and the publication of the collections of ancient Greek vases belonging to the Comte de Caylus and Sir William Hamilton.
Nipt diamond decoration
Nipt diamond wares
Diamond-shaped network decoration made by nipping together ribs or trails of glass threads. A Venetian design but offered by Briton George Ravcnscroft in his 1677 price list of new lead glass. (Above)
Nuppenhecher German,
'drop glass'. A Waldglas drinking glass decorated with applied prunts; made in northern Europe from the 14th century. See also Krautstrunk.
O
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ogee bowl
Bowl for a wine glass shaped with a double curve or an 'S'.
oinochoe
Ancient one-handled jug, often with a trefoil mouth, made in core-formed glass.
opal glass
Translucent white glass made by adding calcined bones to the batch.
opaque twist
See twist.
overlay
The outer layer of glass on cased and flashed glass.
P
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pan-topped
Shape of bowl on some drinking glasses and sweetmeats, in which the upper part of the bow! is wider than the curved lower part.
paperweight
Small solid-glass decorative object used to hold down papers on a desk, originally made in France by Baccarat, Clichy and St Louis during the 'classic' period of paperweight manufacture (1845-55). Beneath a magnifying dome of clear glass (usually lead glass), an orderly millefiori or lampwork design was set low, near the base. The pontil mark on the underside was removed and the resulting slight concavity decorated with cutting (star, strawberry diamond or crosshatching). The dome could be faceted or cased with one or more colors through which windows were cut.
parson or paraison
Bubble of molten glass formed on the blowpipe after air has been blown into it, expanded from the gather.
pate-de-verre
French, 'glass paste'. Ancient technique, revived in France during the second half of the 19th century, of melting in a mold ground glass, to which was added a fluxing medium and coloring agent (this was either powdered, colored glass or metallic oxide).
phial
Roman; small glass bottle used for ointments, medicines and perfumed oils.
phiaie
Greek; shallow bowl with a flat bottom or base-ring used as a wall ornament or for pouring libations-
piggin
Glass with a small bowl and vertical handle that was used as a dipper for milk or cream.
Pilgrim flask
pilgrim flask
Type of bottle with a flattened bulbous body and four loop handles for suspension, intended for use by pilgrims to carry water. The two flattened sides lent themselves to decoration, especially by Venetian enamellers- (Above)
pillar cutting
Style of cut decoration with parallel vertical, convex ribs.
pincering
Technique of pinching or squeezing the trailing or other ornamentation on an object for decorative effect by pincers.
Pokal
German, "goblet*. Usually applied to a late 17th- to mid-19th~century type of engraved, covered goblet with a flared bowl, for drinking toasts.
polishing
Technique of giving a glass object an even finish, either by reintroducing it into the furnace or smoothing it against revolving wheels.
pontil
or punty Solid iron rod to which the object from the blowpipe is transferred so that the rim may be finished, handle applied or any other final shaping carried out. Once the glass has cooled it is knocked off the rod, leaving a rough mark, the 'pontil mark', which, beginning in the 19th century, is usually ground away.
Portland Vase
A dark blue cameo amphora with an opaque white overlay, carved on one side with Paris, his mother Hecuba and the goddess Athena, representing the Fall of Troy, and on the other side, the Rise of Rome with Augustus, his mother Atia (between whose legs rises a snake) and the god Neptune. Possibly made in Rome during the last quarter of the 1st century BC for the emperor Augustus. Formerly in the Palazzo Barberini in Rome and Sir William Hamilton's collection, then sold to the Duke of Portland and the British Museum. Lent to Josiah Wedgwood, whose Black Basalt it inspired.
potash glass
Type of hard glass containing potash (potassium carbonate) derived from plant ash (forest glass); suitable for cutting, unlike cristallo.
press-molding
Technique wherein molten glass is poured into a metal mold and a plunger lowered into the mass, leaving a smooth centre with a patterned exterior. Fine pressed pieces are often finished by hand to obliterate the mold marks. May bear maker's marks.
printy
Below-the-surface pattern of shallow concaves, circular or oval, made with a slightly convex cutting wheel.
prismatic cutting
Decorative cut pattern consisting of long, straight mitred grooves cut horizontally in parallel lines.
Prunts on drinking glass
prunt
Blob of glass, sometimes in a contrasting color, applied to the surface of an object for decoration (Above).
pyxis
Greek; covered receptacle, usually cylindrical, used for cosmetics, ink or jewelry. Made in Roman times in cast, blown or mold-blown glass.
Q
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Queen's Burmese glass
Type of art glass that changes shade from light rose at the top to greenish yellow at the bottom; developed by the Mount Washington Glass Company of Massachusetts and Thomas Webb & Sons in Stourbridge.

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R
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raised diamond-cutting
Decorative cut pattern wherein diagonal grooves arc cut close together and again at right angles to form four-sided diamonds in pyramidal form standing in relief. See also strawberry diamond.
reactive glass
Type of art glass, introduced by Louis Comfort Tiffany, that changed color when reheated.
relief-cutting
Cutting on glass creating a design that stands in relief against the background, as on cameo, Hochschnitt and Tiefschnitt glass.
reticello
See vetro a reticello.
reticulated glass
Decorative glassware on which trails of glass are manipulated to form an open network  Originally a Venetian technique used from the 16th to 18th centuries.
rhyton
Greek; unstable drinking glass, usually made in the form of a human or animal head tapering to a point.
rock crystal engraving
Type of engraving, developed in England at the end of the 19th century by Thomas Webb & Sons and Stevens & Williams, wherein all the surfaces are polished.
Rococo
Probably from the French rocaille, or 'rockwork'. An ornamental style, dating from c.1740 to 1760, that was marked by asymmetry and the use of abstract design suggested by shells, rocks, waves, flowers and foliage.
rod-formed glass
Type of glass made by winding molten glass around a narrow metal rod to make beads.
Roemer
German; traditional 15th- and 16th-century German Waldglas drinking vessel with an ovoid bowl, a hollow cylindrical stem decorated with prunts and a spreading coiled or blown foot.
Rubinglas
German, 'ruby glass'. Glass color with copper, gold or selenium. See Kunckel red.
ruby glass
Related to Rubinglas, introduced by Frederick Carder, in either pink or brilliant red.
rummer
Term usually applied to a 19th-century English low drinking goblet with a square or domed stemmed foot.
Russelbecher German.
See claw-beaker.
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salver
Glass with flat bowl used for displaying foods such as fruit or for supporting jelly glasses.
Scheuer glass
German; type of 15th-century German Waldglas drinking vessel with a wide, cylindrical neck and a bulbous body decorated with prunts, one of which is pulled out to form a handle.
Schwarzlot
German, 'black lead’. Transparent enamel used during the Middle Ages for painting lines and shadows on stained-glass windows and in the l7th and 18th centuries by Hausmaler to decorate glass and porcelain.
Silesian stem
See molded pedestal stem
silica
Silicon dioxide occurring as quartz and as the principal constituent of sand used in the making of glass.
silvered glass
Type of glassware popular in the second half of the 19th century, its silvery appearance created by pouring silver nitrate solution between the double walls of a vessel through a hole in the base, then sealed to prevent oxidization.
Silveria
Type of art glass developed by John Northwood II in c.1900 with silver foil encased between two colorless or colored layers of glass.
silver staining
Technique of applying silver chloride in an acid solution to a glass surface to produce a yellow stain.
Skyphos Greek;
hemispherical or semi-ovoid drinking cup with two handles.
snake thread
Applied trailed decoration in an irregular, sometimes ridged, winding pattern resembling snakes; found on 3rd-cenl;ury Roman glass from Cologne and the Near East.
snowflake
glass 18th-century Chinese glass with white inclusions and bubbles
soda glass
Glass in which the alkali in the batch is obtained from soda (sodium carbonate) rather than potash. In Venetian cristallo the soda is derived from barilla.
sprinkler
flask Glass flask which has a narrow or constricted neck so that the contents can only be poured out slowly or drop by drop.
stained glass
Decorative windows, usually found in churches, made up of colored glass panes further decorated by staining or enamelling and usually held in place by lead cames.
staining
Coloring on the surface of glass achieved by the application of metallic oxides and reheating, like silver staining, to produce yellow or ruby colors by copper oxide. Used since the 14th century on window glass and from the beginning of the 19th century on decorative glass, notably by Anton Kothgasser and the Mohns.
stamnos
Greek; wide-mouthed storage jar with an ovoid body and two loop handles attached at the shoulder.
Stangettglas
German, 'pole glass'. Tall, cylindrical drinking vessel of the 15th and l6th centuries standing on a pedestal base.
star cut
Type of cut decoration with grooves radiating from a central point and tapering outward. The earliest have six to eight points, while later examples have as many as 32.
stippling
Technique of tapping a glass surface with a pointed implement to produce a pattern of tiny dots that build up to make a picture; practiced by Frans Greenwood and David Woiff.
stopper
Piece of glass acting as a cork to a bottle or decanter. Made in a variety of shapes and sizes, such as ball, bull's eye, conical, disc, mushroom and spire.
strawberry diamond
Form of raised diamond-cutting wherein the flat areas between the high-relief diamonds are crosshatched to make a low-relief diamond pattern. Sometimes used on the bases of paperweights.
sulphide
Silvery-looking opaque relief medallion or cameo (usually a portrait) made of a white porcellaneous material enclosed in transparent glass. Because of a thin layer of air under the glass the medallion acquires a silvery appearance.
sweetmeat
Tall-stemmed container used to hold crystallized fruits and a variety of sweetmeats.
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tazza
Italian, 'cup'. Shallow ornamental cup or dish on a stemmed foot, used for fruits or sweetmeats, as a stand for other glasses or possibly for drinking.
Tear bubble in goblet stem
tear
Drop-shaped air bubble enclosed in a glass, usually in the stem. (Above)
trail
Strand of glass, roughly circular in cross section, which has been drawn out from a small gather of glass and applied to the surface of a vessel.
trailing
The laying of threads or trails of hot glass over a glass object to form a decorative pattern.
trulla
Latin; ladle with a round bowl and a horizontal handle.
trunk beaker
See claw-beaker.
turn-over rim
Type of rim curved outward and downward; commonly found on late 18th- to early 19th-century Irish bowls and salt cellars.
twist
Decorative device in the stems of 18th-century drinking glasses and sweetmeats produced by twisting a glass rod in which are embedded columns of air (air-twists and mercury twists), threads of white or colored glass ('cotton-twists', 'color-twists' or opaque twists) or a mixture of the three to give an elaborate multi-spiral.
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uranium glass
Yellowish-green (Annagelb) or green glass (Annagriin) made through the addition of uranium to the batch, introduced in Bohemia by Josef Riedel in around 1840.

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Vandyke
Scalloped decoration on the rims and edges of vessels, derived from the lace collars in Van Dyck's portraits.
verre  eglomise
Decorative technique in which gold or silver leaf is applied to the surface of glass (usually on the reverse), engraved and protected by varnish, metal foil or another layer of glass. So called after French mirror and picture framer Jean-Baptiste Glomy (d.1786). Loosely used to describe types of Zwischengoldglas in jewelry and medallions.
vetro a fili
Italian, "thread glass'. Type of  filigrana
decoration in which clear glass has a pattern of continuous parallel lines.
vetro a reticello bubbles in a grid
vetro a reticello
Italian, 'glass with a small network'. Type of filigrana decoration in which clear glass has a pattern of embedded threads in a diagonal, crisscrossing arrangement trapping small air bubbles between them. (Above)
vetro a retortoli
Italian, 'glass with a twist'. Type of filigrana decoration in which intricately twisted threads are embedded in clear glass in parallel lines.
vitrearius
Latin; glass-blower or glass-maker (as opposed to a diatretarius, or glass-cutter).
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Waldglas
German. See forest glass.
wheel-cutting
Process of decorating glass by means of a rotating wheel that grinds a pattern or inscription into the glass surface.
wheel-engraving
See engraving.
wrythen
Decoration of swirling vertical ribbing that gives a spiral effect.
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Y
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Z
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Zwischengoldglas
German, 'gold between glass'. Decorative technique, found on Bohemian glass (c. 1730-40), wherein gold leaf applied to the outer surface of a glass vessel is engraved with a metal point and protected by being encased in another glass layer or sealed with transparent varnish.

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