Unguentaria were amongst the most common objects of Roman blown glass: produced in large numbers, they were items of everyday use for keeping expensive perfumes and cosmetic oils. The small body and mouth were ideal for slow, careful pouring, while glass was preferred for holding liquids, due to its non-porous, non-absorbent nature. The iridescence on ancient Roman glass was unintentional, and was caused by weathering on its surface. The extent to which a glass object weathers depends mainly on the burial conditions; however, the humidity, heat, and type of soil in which the glass was buried also all affect its preservation.
To find out more about Roman glass please see our relevant blog posts: Ancient Glass and Collecting Ancient Glass
