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, enabling the creation of medicine, incense, and perfume containers in new forms. Along with the unique shapes, different components were added to the hot glass to create a variety of colours. The light blue tint seen in this piece would have been created by adding copper.
To find out more about Roman glass please see our relevant blog post:Ancient Glass and Collecting Roman Glass.