Glass was often the preferred material for storing expensive oils, perfumes, and medicines because it was not porous. The small body and mouth of the vessels allowed the user to carefully pour and control the amount of liquid dispensed. By the 1st century AD, the technique of glass-blowing had revolutionised the art of glass-making. The new technique allowed craftsmen to use smaller amounts of glass for each vessel and obtain much thinner walls, so enabling the creation of small medicine, incense, and perfume containers in new forms. Like this example, originally much of Roman glass vessels were modelled in bluish-green translucent colour, which resulted from the iron oxide present in the silica or the sand. However, other metal oxides could be added to the glass to give it different bright colours.
To find out more about Roman glass please see our relevant blog post: Collecting Roman Glass.