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Cranberry glass and gold ruby glass
The name "cranberry glass" is often connected with the Victorian age. But although some of the most beautiful (and expensive!) collectors items date from that period, cranberry glass already existed long before the Victorian era came into being, and it's still being made today in various countries around the world. The characterisytic color of Cranberry glass is a mild, mellow pinkish red (or reddish pink...), which gave it its other name "gold ruby" glass - which is not badly chosen because in many cases the color or rubies is closely approached. Cranberry glass is very popular for both home decoration and collecting.
Gold ruby glass from Bohemia
It is generally accepted that the glass nowadays known as "cranberry glass", was first produced in Bohemia (the present day Czech Republic) in the early 18th Century. In those days it was usually called gold ruby glass, a name that is still often used in Europe.
During the Victorian period cranberry glass was widely embraced in the United Kingdom, where many styles and designs were developed. Other countries took a liking to the stuff and started production as well, especially from the early 1870's to around 1930 when, apart from traditional Bohemia, large lots of cranberry glas were produced in Belgium, England, France, Bavaria and the USA. It was in the US that the glass got its now most common and popular name. Most American glassworks existed in New England where enormous fields of cranberries are grown, and soon the term cranberry glass was used to describe it's beautiful color. One of the best known American producers of cranberry glass is Fenton, although there are many others that deserve equal fame.
Cranberry glass backgrounds
Cranberry glass or gold ruby glass is made by adding gold(III) chloride to molten glass. Sometimes tiny amounts of tin in the form of stannic chloride are added as a reducing agent. Gold chloride is made by dissolving gold in a solution of nitric acid and hydrochloric acid, producing a colloid. Cranberry glass is typically hand blown or molded. The finished, hardened glass is a type of colloid, a solid phase (in this case gold) dispersed inside another solid phase... in this case of course the glass.
The origins of cranberry glass may date back to the late Roman Empire, although nobody knows for sure. It was (re)discovered in the 17th century by either Johann Knuckel in Bohemia or the Florentine glassmaker Antonio Neri in Italy. Nobody exactly understood the chemistry behind the color, until the later Nobel prize winner of 1925 Richard Adolf Zsigmondy figured out that small colloid gold particles were responsible for the remarkable red color.
As a widely spread myth will have it, cranberry glass was discovered when a wealthy nobleman carelessly flung a gold coin into a vessel full of molten glass. Unfortunately this beautiful myth is nothing but a myth because, as every reader now knows, the gold must first be dissolved in aqua regia, in other words a mixture of hydrochloric and nitric acids, before it makes sense adding it to the molten glass. But hey: it's a beaut story!