Glass became very popular across the Roman Empire, especially after the discovery of glassblowing in which production rates rapidly increase to match the level of demands. Two different trade businesses were involved with the manufacturing of glass, glassmakers and glassworkers. The glassmakers would melt down glass and when cooled, it would be broken into chunks and shipped to glassworkers. Once receiving the glass, the glassworkers would mould it into the desired vessel/object. Different minerals were added to create a variety of colours; the pale blue tint seen in this piece would have been created by adding copper.
Iridescence is often used to date the glass, as it is a consequence of the natural ageing process.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 post:Ancient Roman Glass and Collecting Roman Glass.
