1st.Glass Uranium Vaseline Glass Title Image Uranium Vaseline Glass History and Technical Reference Image


    VASELINE GLASS / URANIUM GLASS - WHAT IS IT ?    


AN EXPLANATION OF WHAT VASELINE GLASS / URANIUM GLASS IS AND WHY IT GLOWS UNDER UV LIGHT

 19th Century English Vaseline Glass Comport Uranium salts (Uranium Dioxide), as found in their natural state, are a vivid yellow. So it's easy to understand why it has been added to glass as a yellow colourant since the early 19th century. There have been claims that its first use was as early as 79 AD following the discovery in 1912 of a glass mosaic in an excavation on a Roman Villa near Naples in Italy but this has never been proven. Some others consider that its first use was by Josef Riedel at his Bohemian glassworks in the 1830's. There is no doubt though, that in 1835 experiments with uranium as a glass colorant were being carried out by Whitefriars Glass Works in London and that in 1836, a pair of uranium glass candlesticks were presented to the Queen. Production of uranium glass in Britain ceased by the end of the second world war but a small amount is still being manufactured in the USA and Czechoslovakia.

HEALTH AND SAFETY ASPECTS OF VASELINE GLASS / URANIUM GLASS   HEALTH AND SAFETY ASPECTS OF VASELINE GLASS / URANIUM GLASS   HEALTH AND SAFETY ASPECTS OF VASELINE GLASS / URANIUM GLASS
One of the most significant aspects of uranium glass is that it is radioactive and does give a positive reading on a geiger counter. This may cause some concern as to its safety with regard to health but I am now able to report that in June 2003 I assisted the UK's National Radiological Protection Board (NRPB) in a study of uranium bearing glass. During this study, technical representatives of the NRPB visited my home and conducted extensive tests on a very wide variety of uranium bearing glass from many manufacturers and time periods. They confirmed that the radiation levels detected were low and quite safe with normal use.

ADDITIONAL SAFETY NOTE: The grinding or abrasive polishing of vaseline glass cannot be classed as 'Normal Use' as the dust and residue produced by these actions can be toxic if inhaled or ingested and therefore should be avoided.

The other significant aspect of uranium bearing glass and that which is of major interest to collectors, is that it glows a vivid bright green under Ultra Violet light (blacklight). This is due to the Ultra Violet radiation exciting the outer electrons of the uranium atoms which as a result give off energy and which is seen by our eyes as a bright green glow. This is called fluorescence. The more intense the UV the brighter the green glow and the less that the original yellow colouring can be seen. Uranium glass also has a slight green glow in daylight due to the Ultra Violet component of daylight acting on it. This glow is paler due to the effect of the other components of white light also striking our eyes.  1930's English Art Deco Vaseline Crackle Glass Cocktail Shaker
 1930's Czech Art Deco Vaseline Glass Candlestick 'Vaseline Glass' is a term that has been adopted for a type of uranium glass which is transparent, has a yellow-green hue in daylight and fluoresces bright green under Ultra-Violet light (black light). So, strictly speaking, anything outside these parameters should just be called 'Uranium Glass'. To further confuse the issue, glass collectors in the UK have adopted the term 'Vaseline Glass' to describe opalescent glass. To avoid confusion I always refer to any glass with opalescence as 'opalescent glass'.

Apart from vaseline glass there are many other types of uranium bearing glass, some of which have also been given names. For example some opaque uranium glass tends to be called 'Custard Glass' and if it also has a pink tinged satin area to part of it (caused by gold in the mix being reheated), then it may well be termed 'Burmese Glass'.  c.1938 Jobling Art Deco Vaseline Glass Posy Bowl

 Victorian Gilt Ormulu Mounted Vaseline Glass Pot The higher the uranium dioxide content in the glass then naturally the greater the coloring effect is, which can exclude some transparent glass from the vaseline glass definition because the yellow colour is so dominant. Other colourants were often added to glass in addition to the uranium dioxide. The colour yellow is formed by Red+Green, so when a green colourant is also added, green then becomes the dominant colour of the glass, yet it will still fluoresce bright green under Ultra Violet light (blacklight). Other combinations of colour are rarer but I have found shades of amber, blue, turquoise, pink, white and grey glass all with a positive uranium dioxide content (Confirmed by testing with a geiger counter)and all fluoresced a brilliant green under Ultra Violet light (blacklight) except for uranium glass with a high lead content which exhibits a reduction in green glow due to the damping effect of the lead.

I have always tested all the period and antique vaseline glass or uranium glass I sell with a geiger counter and Longwave UV (blacklight), to confirm that the glow was caused by uranium dioxide and not Manganese or some other chemical, as could occur. As a result I have built up a sizeable database of test results. So as to show the large range of shapes, hues and uranium dioxide content of period and antique vaseline glass / uranium glass there is a table of geiger counter tested uranium glass pieces on the 1st.Glass website. There is also a Uranium / Vaseline Glass photo gallery in the Glass Photo Galleries on the website

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