‘Roman glass was created around 2,000 years ago, using a glass-blowing technique still in use today,’ explains specialist Laetitia Delaloye, introducing a selection of rare pieces to feature in Christie’s Antiquities sale on 6 July.
The form, colour and function of these detailed works, explains Delaloye, varies immensely: ‘Some were used as drinking vessels, while others became perfume bottles. Miniature vessels would be used as charms, or even worn as pendants.’
For collectors, ‘some colours are rarer than others’. Delaloye cites the brilliance of amber pieces that shine like gold, or works in deep aubergine. ‘Cobalt blue was the most expensive to produce, and therefore the rarest,’ she adds. ‘Whenever you find a cobalt-blue vessel you know you’ve got something special.’
The age of the vessels, and where they are found, can also contribute to a richly coloured surface. ‘The glass can have what we call iridescence, where it has oxidised,’ says Delaloye. ‘It's a good sign that a piece may have been underground for almost 2,000 years before being discovered.’
In this video, Delaloye demonstrates how the condition of ancient glass is assessed using UV light, and explains how rare artist signatures can reveal details about the history of an object — as well as its value. ‘When you start collecting you get to know so much about the pieces you own,’ she adds. ‘It can become addictive.’