Glass is an amorphous (non-crystalline) solid. Because it is often transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware, and optics. Some common objects made of glass are named after the material, e.g., a "glass" for drinking, "glasses" for vision correction, and a "magnifying glass".
Glass is most often formed by rapid cooling (quenching) of the Melting form. Some glasses such as volcanic glass are naturally occurring, and obsidian has been used to make arrowheads and knives since the Stone Age. Archaeological evidence suggests glassmaking dates back to at least 3600 BC in Mesopotamia, Ancient Egypt, or Syria. The earliest known glass objects were beads, perhaps created accidentally during metalworking or the production of faience, which is a form of pottery using lead glazes.
Due to its ease of formability into any shape, glass has been traditionally used for vessels, such as bowls, , , jars and drinking glasses. Soda–lime glass, containing around 70% Silicon dioxide, accounts for around 90% of modern manufactured glass. Glass can be coloured by adding metal salts or painted and printed with , leading to its use in stained glass windows and other glass art objects.
The refraction, reflective and transmission properties of glass make glass suitable for manufacturing optical lenses, prisms, and optoelectronics materials. Extruded glass fiber have applications as optical fiber in communications networks, thermal insulating material when matted as glass wool to trap air, or in glass-fibre reinforced plastic (fiberglass).
Microscopic structure
The standard definition of a
glass (or vitreous solid) is a non-crystalline solid formed by rapid melt
quenching.
[ASTM definition of glass from 1945] However, the term "glass" is often defined in a broader sense, to describe any non-crystalline (
amorphous solid) solid that exhibits a
glass transition when heated towards the liquid state.
Glass is an amorphous solid. Although the atomic-scale structure of glass shares characteristics of the structure of a supercooled liquid, glass exhibits all the mechanical properties of a solid.["Philip Gibbs" Glass Worldwide, (May/June 2007), pp. 14–18] As in other , the atomic structure of a glass lacks the long-range periodicity observed in crystalline solids. Due to chemical bonding constraints, glasses do possess a high degree of short-range order with respect to local atomic polyhedra.
Formation from a supercooled liquid
For melt quenching, if the cooling is sufficiently rapid (relative to the characteristic
crystallization time) then crystallization is prevented and instead, the disordered atomic configuration of the
supercooled liquid is frozen into the solid state at T
g. The tendency for a material to form a glass while quenched is called glass-forming ability. This ability can be predicted by the rigidity theory.
Generally, a glass exists in a structurally metastable state with respect to its
Crystallinity form, although in certain circumstances, for example in
atactic polymers, there is no crystalline analogue of the amorphous phase.
Glass is sometimes considered to be a liquid due to its lack of a first-order phase transition
Occurrence in nature
Glass can form naturally from volcanic magma.
Obsidian is a common volcanic glass with high silica (SiO
2) content formed when felsic lava extruded from a volcano cools rapidly.
is a form of glass formed by the impact of a
meteorite, where
Moldavite (found in central and eastern Europe), and Libyan desert glass (found in areas in the eastern
Sahara, the
Libyan desert and western Egypt) are notable examples.
of
quartz can also occur when
lightning strikes
sand, forming hollow, branching rootlike structures called
.
is a glassy residue formed from the desert floor sand at the
Trinity test nuclear testing site.
, found in
South Australia, is proposed to originate from
Pleistocene grassland fires,
lightning strikes, or hypervelocity impact by one or several
or
.
File:Lipari-Obsidienne (5).jpg|A piece of volcanic obsidian glass
File:Moldavite Besednice.jpg|Moldavite, a natural glass formed by meteorite impact, from Besednice, Bohemia proper
File:Fulgurites-algeria.jpg|Tube fulgurites
File:Trinitite from Trinity Site.jpg|Trinitite, a glass made by the Trinity nuclear-weapon test
File:Libyan Desert Glass.jpg|Libyan desert glass
History
Naturally occurring
obsidian glass was used by
Stone Age societies as it fractures along very sharp edges, making it ideal for cutting tools and weapons.
Glassmaking dates back at least 6000 years, long before humans had discovered how to Smelting iron.
Early glass was rarely transparent and often contained impurities and imperfections,
During the Late Bronze Age, there was a rapid growth in glassmaking technology in Egypt and Western Asia.
Much early glass production relied on grinding techniques borrowed from Stonemasonry, such as grinding and carving glass in a cold state.[Wilde, H. "Technologische Innovationen im 2. Jahrtausend v. Chr. Zur Verwendung und Verbreitung neuer Werkstoffe im ostmediterranen Raum". GOF IV, Bd 44, Wiesbaden 2003, 25–26.]
The term glass has its origins in the late Roman Empire, in the Roman glass making centre at Trier (located in current-day Germany) where the late-Latin term glesum originated, likely from a Germanic word for a transparent, lustrous substance.[Aton, Francesca, Perfectly Preserved 2,000-Year-Old Roman Glass Bowl Unearthed in the Netherlands, Art News, January 25, 2022][McGreevy, Nora, 2,000-Year-Old Roman Bowl Discovered Intact in the Netherlands, National Geographic, January 28, 2022] Examples of Roman glass have been found outside of the former Roman Empire in China,
In post-classical West Africa, Benin was a manufacturer of glass and glass beads.[Oliver, Roland, and Fagan, Brian M. Africa in the Iron Age, c500 B.C. to A.D. 1400. New York: Cambridge University Press, p. 187. .]
Glass was used extensively in Europe during the Middle Ages. Anglo-Saxon glass has been found across England during archaeological excavations of both settlement and cemetery sites.
During the 13th century, the island of Murano, Venice, became a centre for glass making, building on medieval techniques to produce colourful ornamental pieces in large quantities.
Throughout the 20th century, new mass production techniques led to the widespread availability of glass in much larger amounts, making it practical as a building material and enabling new applications of glass.
In the 21st century, glass manufacturers have developed different brands of chemically strengthened glass for widespread application in for , , and many other types of information appliances. These include Gorilla Glass, developed and manufactured by Corning, AGC Inc.'s Dragontrail and Schott AG's Xensation.
Physical properties
Optical
Glass is in widespread use in optical systems due to its ability to refract, reflect, and transmit light following geometrical optics. The most common and oldest applications of glass in optics are as lenses,
,
, and prisms.
The key optical properties
refractive index, dispersion, and transmission, of glass are strongly dependent on chemical composition and, to a lesser degree, its thermal history.
Optical glass typically has a refractive index of 1.4 to 2.4, and an
Abbe number (which characterises dispersion) of 15 to 100.
The refractive index may be modified by high-density (refractive index increases) or low-density (refractive index decreases) additives.
Glass transparency results from the absence of grain boundary which diffusely scatter light in polycrystalline materials.
Other
In the manufacturing process, glasses can be poured, formed, extruded and moulded into forms ranging from flat sheets to highly intricate shapes.
The finished product is brittle but can be
laminated glass or
Tempered glass to enhance durability.
Glass is typically inert, resistant to chemical attack, and can mostly withstand the action of water, making it an ideal material for the manufacture of containers for foodstuffs and most chemicals.
Nevertheless, although usually highly resistant to chemical attack, glass will corrode or dissolve under some conditions.
The materials that make up a particular glass composition affect how quickly the glass corrodes. Glasses containing a high proportion of
alkali metal or alkaline earth elements are more susceptible to corrosion than other glass compositions.
The density of glass varies with chemical composition with values ranging from for Fused quartz to for dense flint glass.
Reputed flow
The observation that old windows are sometimes found to be thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a timescale of centuries, the assumption being that the glass has exhibited the liquid property of flowing from one shape to another.
This assumption is incorrect, as once solidified, glass stops flowing. The sags and ripples observed in old glass were already there the day it was made; manufacturing processes used in the past produced sheets with imperfect surfaces and non-uniform thickness (the near-perfect
float glass used today only became widespread in the 1960s).
A 2017 study computed the rate of flow of the medieval glass used in Westminster Abbey from the year 1268. The study found that the room temperature viscosity of this glass was roughly 1024Pa·Second which is about 1016 times less viscous than a previous estimate made in 1998, which focused on soda-lime silicate glass. Even with this lower viscosity, the study authors calculated that the maximum flow rate of medieval glass is 1 Nanometer per billion years, making it impossible to observe in a human timescale.
Types
Silicate glasses
Silicon dioxide (SiO
2) is a common fundamental constituent of glass.
Fused quartz is a glass made from chemically pure silica.
It has very low thermal expansion and excellent resistance to
thermal shock, being able to survive immersion in water while red hot, resists high temperatures (1000–1500 °C) and chemical weathering, and is very hard. It is also transparent to a wider spectral range than ordinary glass, extending from the visible further into both the UV and
Infrared ranges, and is sometimes used where transparency to these wavelengths is necessary. Fused quartz is used for high-temperature applications such as furnace tubes, lighting tubes, melting crucibles, etc.
However, its high melting temperature (1723 °C) and viscosity make it difficult to work with. Therefore, normally, other substances (fluxes) are added to lower the melting temperature and simplify glass processing.
Soda–lime glass
Sodium carbonate (Na
2CO
3, "soda") is a common additive and acts to lower the glass-transition temperature. However,
sodium silicate is
water solubility, so lime (CaO,
calcium oxide, generally obtained from
limestone), along with
magnesium oxide (MgO), and
aluminium oxide (Al
2O
3), are commonly added to improve chemical durability. Soda–lime glasses (Na
2O) + lime (CaO) + magnesia (MgO) + alumina (Al
2O
3) account for over 75% of manufactured glass, containing about 70 to 74% silica by weight.
[B.H.W.S. de Jong, "Glass"; in "Ullmann's Encyclopedia of Industrial Chemistry"; 5th edition, vol. A12, VCH Publishers, Weinheim, Germany, 1989, , pp. 365–432.] Soda–lime–silicate glass is transparent, easily formed, and most suitable for window glass and tableware.
However, it has a high thermal expansion and poor resistance to heat.
Soda–lime glass is typically used for
,
,
, and
.
Borosilicate glass
Borosilicate glasses (e.g.
Pyrex, Duran) typically contain 5–13%
boron trioxide (B
2O
3).
Borosilicate glasses have fairly low coefficients of thermal expansion (7740 Pyrex CTE is 3.25/°C
as compared to about 9/°C for a typical soda–lime glass
). They are, therefore, less subject to stress caused by thermal expansion and thus less vulnerable to cracking from
thermal shock. They are commonly used for e.g.
labware,
cookware, and sealed beam car
.
Lead glass
The addition of lead(II) oxide into silicate glass lowers the melting point and
viscosity of the melt.
The high density of lead glass (silica + lead oxide (PbO) + potassium oxide (K
2O) + soda (Na
2O) + zinc oxide (ZnO) + alumina) results in a high electron density, and hence high refractive index, making the look of glassware more brilliant and causing noticeably more specular reflection and increased optical dispersion.
Lead glass has a high elasticity, making the glassware more workable and giving rise to a clear "ring" sound when struck. However, lead glass cannot withstand high temperatures well.
Lead oxide also facilitates the solubility of other metal oxides and is used in coloured glass. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glass); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in
and
. The high
ionic radius of the Pb
2+ ion renders it highly immobile and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda–lime glass (10
8.5 vs 10
6.5 Ω⋅cm,
direct current at 250 °C).
Aluminosilicate glass
Aluminosilicate glass typically contains 5–10%
alumina (Al
2O
3). Aluminosilicate glass tends to be more difficult to melt and shape compared to borosilicate compositions but has excellent thermal resistance and durability.
Aluminosilicate glass is extensively used for
fiberglass,
used for making glass-reinforced plastics (boats, fishing rods, etc.), top-of-stove cookware, and halogen bulb glass.
Other oxide additives
The addition of
barium also increases the refractive index.
Thorium oxide gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its
radioactivity has been replaced by
lanthanum oxide in modern eyeglasses.
Iron can be incorporated into glass to absorb
infrared radiation, for example in heat-absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs
ultraviolet wavelengths.
lowers the dielectric constant of glass. Fluorine is highly
electronegative and lowers the polarizability of the material. Fluoride silicate glasses are used in the manufacture of integrated circuits as an insulator.
Glass-ceramics
Glass-ceramic materials contain both non-crystalline glass and
Crystallinity ceramic phases. They are formed by controlled nucleation and partial crystallisation of a base glass by heat treatment.
Crystalline grains are often embedded within a non-crystalline intergranular phase of
grain boundary. Glass-ceramics exhibit advantageous thermal, chemical, biological, and dielectric properties as compared to metals or organic polymers.
The most commercially important property of glass-ceramics is their imperviousness to thermal shock. Thus, glass-ceramics have become extremely useful for countertop cooking and industrial processes. The negative thermal expansion coefficient (CTE) of the crystalline ceramic phase can be balanced with the positive CTE of the glassy phase. At a certain point (~70% crystalline) the glass-ceramic has a net CTE near zero. This type of glass-ceramic exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C.
Fibreglass
Fibreglass (also called glass fibre reinforced plastic, GRP) is a composite material made by reinforcing a plastic
resin with
. It is made by melting glass and stretching the glass into fibres. These fibres are woven together into a cloth and left to set in a plastic resin.
Fibreglass has the properties of being lightweight and corrosion resistant and is a good insulator enabling its use as building insulation material and for electronic housing for consumer products. Fibreglass was originally used in the United Kingdom and United States during World War II to manufacture
. Uses of fibreglass include building and construction materials, boat hulls, car body parts, and aerospace composite materials.
Glass wool is an excellent thermal and sound insulation insulation material, commonly used in buildings (e.g. attic and cavity wall insulation), and plumbing (e.g. pipe insulation), and soundproofing.
Non-silicate glasses
Besides common silica-based glasses many other
inorganic and organic materials may also form glasses, including
Metallic glass,
,
,
, chalcogenides,
, germanates (glasses based on
Germanium oxide), tellurites (glasses based on TeO
2), antimonates (glasses based on Sb
2O
3), arsenates (glasses based on As
2O
3), titanates (glasses based on TiO
2), tantalates (glasses based on Ta
2O
5),
,
,
plastics,
acrylic glass, and many other substances.
Some of these glasses (e.g. Germanium dioxide (GeO
2, Germania), in many respects a structural analogue of silica,
fluoride glass,
aluminate,
phosphate glass,
borate glass, and chalcogenide glasses) have physicochemical properties useful for their application in
Optical fiber in communication networks and other specialised technological applications.
Silica-free glasses may often have poor glass-forming tendencies. Novel techniques, including containerless processing by aerodynamic levitation (cooling the melt whilst it floats on a gas stream) or splat quenching (pressing the melt between two metal anvils or rollers), may be used to increase the cooling rate or to reduce crystal nucleation triggers.
Amorphous metals
In the past, small batches of
with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. Amorphous metal wires have been produced by sputtering molten metal onto a spinning metal disk.
Several alloys have been produced in layers with thicknesses exceeding 1 millimetre. These are known as bulk metallic glasses (BMG). Liquidmetal sells several zirconium-based BMGs.
Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys.
Experimental evidence indicates that the system Al-Fe-Si may undergo a first-order transition to an amorphous form (dubbed "q-glass") on rapid cooling from the melt. Transmission electron microscopy (TEM) images indicate that q-glass nucleates from the melt as discrete particles with uniform spherical growth in all directions. While x-ray diffraction reveals the isotropic nature of q-glass, a nucleation barrier exists implying an interfacial discontinuity (or internal surface) between the glass and melt phases.
Polymers
Important
polymer glasses include amorphous and glassy pharmaceutical compounds. These are useful because the solubility of the compound is greatly increased when it is amorphous compared to the same crystalline composition. Many emerging pharmaceuticals are practically insoluble in their crystalline forms.
Many polymer
familiar to everyday use are glasses. For many applications, like
glass bottles or
eyewear, polymer glasses (
acrylic glass,
polycarbonate or polyethylene terephthalate) are a lighter alternative to traditional glass.
Molecular liquids and molten salts
Molecular liquids,
,
, and
are mixtures of different
molecules or
that do not form a covalent network but interact only through weak van der Waals forces or transient
. In a mixture of three or more ionic species of dissimilar size and shape, crystallization can be so difficult that the liquid can easily be supercooled into a glass.
Examples include LiCl:
RH
2O (a solution of
lithium chloride salt and water molecules) in the composition range 4<
R<8.
[ European Workshop on Glasses and Gels.] sugar glass,
or Ca
0.4K
0.6(NO
3)
1.4.
Glass electrolytes in the form of Ba-doped Li-glass and Ba-doped Na-glass have been proposed as solutions to problems identified with organic liquid electrolytes used in modern lithium-ion battery cells.
Production
Following the
glass batch preparation and mixing, the raw materials are transported to the furnace. Soda–lime glass for
mass production is melted in glass-melting furnaces. Smaller-scale furnaces for speciality glasses include electric melters, pot furnaces, and day tanks.
After melting, homogenization and refining (removal of bubbles), the glass is . This may be achieved manually by
glassblowing, which involves gathering a mass of hot semi-molten glass, inflating it into a bubble using a hollow blowpipe, and forming it into the required shape by blowing, swinging, rolling, or moulding. While hot, the glass can be worked using hand tools, cut with shears, and additional parts such as handles or feet attached by welding.
for windows and similar applications is formed by the
float glass process, developed between 1953 and 1957 by Sir Alastair Pilkington and Kenneth Bickerstaff of the UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish.
for common bottles and jars is formed by blowing and pressing methods.
This glass is often slightly modified chemically (with more alumina and calcium oxide) for greater water resistance.
Once the desired form is obtained, glass is usually annealed for the removal of stresses and to increase the glass's hardness and durability.
New chemical glass compositions or new treatment techniques can be initially investigated in small-scale laboratory experiments. The raw materials for laboratory-scale glass melts are often different from those used in mass production because the cost factor has a low priority. In the laboratory mostly pure are used. Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment (such as alkali metal or alkaline earth metal oxides and hydroxides, or boron trioxide), or that the impurities are quantified (loss on ignition).
Colour
Colour in glass may be obtained by addition of homogenously distributed electrically charged ions (or colour centres). While ordinary soda–lime glass appears colourless in thin section, iron(II) oxide (FeO) impurities produce a green tint in thick sections.
Manganese dioxide (MnO
2), which gives glass a purple colour, may be added to remove the green tint given by FeO.
FeO and chromium(III) oxide (Cr
2O
3) additives are used in the production of green bottles.
Iron (III) oxide, on the other-hand, produces yellow or yellow-brown glass.
Low concentrations (0.025 to 0.1%) of
cobalt oxide (CoO) produce rich, deep blue
cobalt glass.
is a very powerful colouring agent, yielding dark green.
[ Chemical Fact Sheet – Chromium www.speclab.com.]
Sulphur combined with
carbon and iron salts produces amber glass ranging from yellowish to almost black.
[David M Issitt. Substances Used in the Making of Coloured Glass 1st.glassman.com.] A glass melt can also acquire an amber colour from a reducing combustion atmosphere.
produces imperial
red, and combined with selenium can produce shades of yellow, orange, and red.
Addition of copper(II) oxide (CuO) produces a turquoise colour in glass, in contrast to copper(I) oxide (Cu
2O) which gives a dull red-brown colour.
File:Bottle, wine (AM 1997.80.28-1).jpg|alt=A green glass bottle|Iron(II) oxide and chromium(III) oxide additives are often used in the production of green bottles.
Uses
Architecture and windows
Soda–lime
Plate glass is typically used as a transparent glazing material, typically as
in external walls of buildings. Float or rolled sheet glass products are cut to size either by scoring and snapping the material,
laser cutting, water jets, or
diamond blade saw. The glass may be thermally or chemically
Tempered glass (strengthened) for
safety glass and bent or curved during heating. Surface coatings may be added for specific functions such as scratch resistance, blocking specific wavelengths of light (e.g.
infrared or
ultraviolet), dirt-repellence (e.g. self-cleaning glass), or switchable
Electrochromism coatings.
Structural glazing systems represent one of the most significant architectural innovations of modern times, where glass buildings now often dominate the of many modern cities.
Tableware
Glass is an essential component of tableware and is typically used for water,
Beer glassware and
wine glass drinking glasses.
Wine glasses are typically
stemware, i.e. goblets formed from a bowl, stem, and foot.
Lead crystal glass may be cut and polished to produce decorative drinking glasses with gleaming facets.
Other uses of glass in tableware include
decanters,
, plates, and
.
File:Jubilee Campus MMB «62 Melton Hall Christmas Dinner.jpg|Wine glasses and other glass tableware
File:British dimpled glass pint jug with ale.jpg|Dimpled glass beer pint jug
File:Crystal glass.jpg|Cut glass
File:Decanter and Stopper LACMA 56.35.29a-b.jpg|A glass decanter and Bung
Packaging
The inert and impermeable nature of glass makes it a stable and widely used material for food and drink packaging as
and
. Most
container glass is soda–lime glass, produced by blowing and pressing techniques. Container glass has a lower
magnesium oxide and
sodium oxide content than flat glass, and a higher
silica,
calcium oxide, and
aluminum oxide content.
["High temperature glass melt property database for process modeling"; Eds.: Thomas P. Seward III and Terese Vascott; The American Ceramic Society, Westerville, Ohio, 2005, ] Its higher content of water-insoluble oxides imparts slightly higher chemical durability against water, which is advantageous for storing beverages and food. Glass packaging is sustainable, readily recycled, reusable and refillable.
For electronics applications, glass can be used as a substrate in the manufacture of integrated passive devices, thin-film bulk acoustic resonators, and as a material in device packaging,
Laboratories
Glass is an important material in scientific laboratories for the manufacture of experimental apparatus because it is relatively cheap, readily formed into required shapes for experiment, easy to keep clean, can withstand heat and cold treatment, is generally non-reactive with many
, and its transparency allows for the observation of chemical reactions and processes.
Laboratory glassware applications include
Laboratory flask,
,
,
, graduated cylinders, glass-lined metallic containers for chemical processing, fractionation columns, glass pipes,
, gauges, and
.
Although most standard laboratory glassware has been mass-produced since the 1920s, scientists still employ skilled
to manufacture bespoke glass apparatus for their experimental requirements.
File:Vigreux column lab.jpg|A Vigreux column in a laboratory setup
File:Double vac line front view.jpg|A Schlenk line with four ports
File:Different types of graduated cylinder- 10ml, 25ml, 50ml and 100 ml graduated cylinder.jpg|Graduated cylinders
File:250 mL Erlenmeyer flask.jpg|Erlenmeyer Laboratory flask
Optics
Glass is a ubiquitous material in
optics because of its ability to
Refraction, reflect, and
Transmittance light. These and other optical properties can be controlled by varying chemical compositions, thermal treatment, and manufacturing techniques. The many applications of glass in optics include
glasses for eyesight correction, imaging optics (e.g.
and
in
,
, and
),
fibre optics in telecommunications technology, and integrated optics.
and gradient-index optics (where the
refractive index is non-uniform) find application in e.g. reading
,
,
, and
.
Modern glass art
The 19th century saw a revival in ancient glassmaking techniques including
cameo glass, achieved for the first time since the Roman Empire, initially mostly for pieces in a
neoclassicism style. The
Art Nouveau movement made great use of glass, with René Lalique, Émile Gallé, and Daum of Nancy in the first French wave of the movement, producing coloured vases and similar pieces, often in cameo glass or
lustre glass techniques.
Louis Comfort Tiffany in America specialised in stained glass, both secular and religious, in panels and his famous lamps. The early 20th century saw the large-scale factory production of glass art by firms such as Waterford and Lalique. Small studios may hand-produce glass artworks. Techniques for producing glass art include glassblowing, kiln-casting, fusing, slumping, pâte de verre, flame-working, hot-sculpting and cold-working. Cold work includes traditional stained glass work and other methods of shaping glass at room temperature. Objects made out of glass include vessels, paperweights, marbles, , sculptures and installation art.
Image:Portland Vase BM Gem4036 n5.jpg|The Portland Vase, Roman cameo glass, about 5–25 AD
File:Medallion St Demetrios Louvre OA6457.jpg|Byzantine cloisonné enamel plaque of St Demetrios, c. 1100, using the senkschmelz or "sunk" technique
File:Gallé, nancy, vaso clematis, 1890-1900.JPG|Émile Gallé, Marquetry glass vase with clematis flowers (1890–1900)
File:Vase (Perruches) by René Jules Lalique, 1922, blown four mold glass - Cincinnati Art Museum - DSC04355.JPG|Glass vase by Art Nouveau artist René Lalique
File:Clara driscoll per tiffany studios, lampada laburnum, 1910 ca. 02.jpg|Clara Driscoll Tiffany lamp, laburnum pattern, c. 1910
File:Glass.sculpture.kewgardens.london.arp.jpg|A glass sculpture by Dale Chihuly, The Sun, at the "Gardens of Glass" exhibition in Kew Gardens, London
See also
External links
