![]() ![]() ![]() The Cambridge Glass Company used cobalt for their Royal Blue and their Moonlight Blue. So isįenton's Royal Blue and Periwinkle Blue (both from the 1930s), their Blue Silvertone in the Sheffield pattern and Velva Blue from 1981. Fenton's blue carnival glass is a cobalt blue. There are many famous types of blue-colored glass which are in fact cobalt blue glass. Cobalt aluminate makes turquoise glass cobalt silicate produces violet-blue glass.Ĭobalt oxide added to borosilicate glass produces a purple or red glass. Whilst cobalt oxide produces a deep royal blue, there are other compounds of cobalt which produce different colors. This deep blue glass can then be ground up into a powder called "SMALT" which is used as a coloring agent for enamel, for glazes on pottery, and for making more blue glass. Deeper blues are obtained by adding up to ten pounds of cobalt oxide to a ton of glass. To produce a blue colour in glass, you only need to add five ounces to a ton of glass. Small amounts of cobalt (around 1 ounce per ton of glass) are used to neutralise the yellow tint of iron in glass such as window glass. Surprisingly it also makes up 4.3% of vitamin B12. Since then it has been used increasingly in metal alloys, and over 80% of today's production of cobalt is used as a metal, - it is, for example, a component of the best magnets. There was even one piece of cobalt blue glass in Tut-Ankh-Amen's tomb in Egypt.īefore the 1920s the world's production of cobalt was primarily used as a glass and ceramic colorant. It was discovered by a Swedish chemist, Georg Brandt, in 1742 although the coloring properties of the ore has been known since very ancient times. ![]() It only requires a small amount of cobalt oxide to produce a deep rich blue.Ĭobalt is a metal, found in copper and nickel ores in many countries, but mined chiefly in Africa, USSR, Australia, Canada and smaller amounts in other countries. Copper is a more delicate colorant than cobalt. Most blue glass is given its color either from cobalt oxide or from copper oxide added to the molten glass. It is made by incorporating cobalt oxide in the molten glass mixture. Cobalt Blue Glass information from the Glass EncyclopediaĬobalt blue glass is normally a deep rich blue like the vase on the left. ![]()
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