Cranberry glass or Gold Ruby glass is a red glass made by adding

gold salts Gold-containing drugs are pharmaceuticals that contain gold. Sometimes these species are referred to as "gold salts". "Chrysotherapy" and "aurotherapy" are the applications of gold compounds to medicine. Research on the medicinal effects of g ...

colloidal gold Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid, usually water. The colloid is usually either wine-red coloured (for spherical particles less than 100 nm) or blue/purple (for larger spherical particl ...

to molten glass.

Tin Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal. Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...

, in the form of

stannous chloride Tin(II) chloride, also known as stannous chloride, is a white crystalline solid with the formula . It forms a stable dihydrate, but aqueous solutions tend to undergo hydrolysis, particularly if hot. SnCl2 is widely used as a reducing agent (in acid ...

, is sometimes added in tiny amounts as a

reducing agent In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are commonly reducing agents include the Earth meta ...

. The glass is used primarily in expensive decorations.

Production

Cranberry glass is made in

craft production Craft production is manufacturing by hand, with or without the aid of tools. The term "craft production" describes manufacturing techniques that are used in handicraft trades. They were the common methods of manufacture in the pre-industrialized ...

rather than in large quantities, due to the high cost of the gold. The gold chloride is made by dissolving gold in a solution of nitric acid and hydrochloric acid ( aqua regia). The glass is typically hand blown or molded. The finished, hardened glass is a type of

colloid A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others extend ...

, a solid phase (

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

) dispersed inside another solid phase (

glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...

History

The origins of cranberry glass making are unknown, but many historians believe a form of this glass was first made in the late

Roman Empire The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterr ...

. This is evidenced by the

British Museum The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest and most comprehensive in existence. It docum ...

's collection

Lycurgus Cup The Lycurgus Cup is a 4th-century Roman glass cage cup made of a dichroic glass, which shows a different colour depending on whether or not light is passing through it: red when lit from behind and green when lit from in front. It is the only c ...

, a 4th-century

Roman glass Roman glass objects have been recovered across the Roman empire, Roman Empire in domestic, industrial and funerary contexts. Glass was used primarily for the production of vessels, although mosaic tiles and window glass were also produced. Roman g ...

cage cup A cage cup, also ''vas diatretum'', plural ''diatreta'', or "reticulated cup" is a type of luxury late Roman glass vessel, found from roughly the 4th century, and "the pinnacle of Roman achievements in glass-making". ''Diatreta'' consist of a ...

made of a

dichroic glass Dichroic glass is glass which can display multiple different colors depending on lighting conditions. One dichroic material is a modern composite non-translucent glass that is produced by stacking layers of metal oxides which give the glass shift ...

, which shows a different colour depending on whether light is passing through it or reflecting from it; red (gold salts) when lit from behind and green (silver salts) when lit from in front. The craft was then lost and rediscovered in the 17th century

Bohemia Bohemia ( ; cs, Čechy ; ; hsb, Čěska; szl, Czechy) is the westernmost and largest historical region of the Czech Republic. Bohemia can also refer to a wider area consisting of the historical Lands of the Bohemian Crown ruled by the Bohem ...

n period by either Johann Kunckel in

Potsdam Potsdam () is the capital and, with around 183,000 inhabitants, largest city of the German state of Brandenburg. It is part of the Berlin/Brandenburg Metropolitan Region. Potsdam sits on the River Havel, a tributary of the Elbe, downstream of B ...

or by the Florentine glassmaker Antonio Neri. Neither of them knew the mechanism which yielded the colour, however. Chemist and winner of the 1925

Nobel Prize in Chemistry ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "M ...

Richard Adolf Zsigmondy Richard Adolf Zsigmondy ( hu, Zsigmondy Richárd Adolf; 1 April 1865 – 23 September 1929) was an Austrian-born chemist. He was known for his research in colloids, for which he was awarded the Nobel Prize in chemistry in 1925, as well as for c ...

was able to understand and explain that small

s of gold were responsible for the red colour. The most famous period of cranberry glass production was in 19th century

Britain Britain most often refers to: * The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands * Great Britain, the largest island in the United King ...

during the

Victorian Era In the history of the United Kingdom and the British Empire, the Victorian era was the period of Queen Victoria's reign, from 20 June 1837 until her death on 22 January 1901. The era followed the Georgian period and preceded the Edwardia ...

. Legend holds that cranberry glass was first discovered when a noble tossed a gold coin into a mixture of molten glass. This legend is almost certainly not true, as the gold must be dissolved in aqua regia before being added to the molten glass. Cranberry glass creations were most popular as a table display, often holding

candy Candy, also called sweets (British English) or lollies (Australian English Australian English (AusE, AusEng, AuE, AuEng, en-AU) is the set of varieties of the English language native to Australia. It is the country's common language an ...

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s. Cranberry glass was also frequently used for wine glasses,

decanter A decanter is a vessel that is used to hold the decantation of a liquid (such as wine) which may contain sediment. Decanters, which have a varied shape and design, have been traditionally made from glass or crystal. Their volume is usually equ ...

s, and

finger bowl A finger is a limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers (Pentadactyly). Chambers 1 ...

s. Cranberry glass was also well known for its use in " Mary Gregory" glass. This glass had a white enamel fired onto the glass in a design, usually with a romantic theme.

References

External links

* * * {{DEFAULTSORT:Cranberry Glass Glass art Glass trademarks and brands Glass compositions Craft materials

Production

History

See also

References

External links