The invention of glass-blowing revolutionised the art of glass-making in the 1st century BC. The new technique allowed craftsmen to use smaller amounts of glass for each vessel and obtain much thinner walls, so enabling the creation of a variety of glass containers in new forms. Different minerals were added to create a variety of colours; the green-blue tint seen in this piece would have been created by adding iron or copper and changing the oxygen levels. Flasks such as this fine example would have stored cosmetics or drinking products, and were used by households and merchants across the Roman Empire.
To find out more about Roman glass please see our relevant blog posts: Ancient Glass and Collecting Guide: Ancient Roman Glass