Roman Glass
Read this article about the history and evolution of Roman glass production. The manufacture of glassware was known throughout the ancient world, but Roman artisans produced glass on an unprecedented scale. During the first century BCE, the invention of glassblowing allowed artisans to quickly create glass products in a wide range of shapes, bringing cheap glass to mass markets.
Production
Styles
Glass vessel from the 2nd century AD, found in Bosanski Novi
The earliest Roman glass follows Hellenistic traditions and uses strongly coloured and 'mosaic' patterned glass. During the late Republican period new highly coloured striped wares with a fusion of dozens of monochrome and lace-work strips were introduced. During this period there is some evidence that styles of glass varied geographically, with the translucent coloured fine wares of the early 1st century notably 'western' in origin, whilst the later colourless fine wares are more 'international'. These objects also represent the first with a distinctly Roman style unrelated to the Hellenistic casting traditions on which they are based, and are characterised by novel rich colours. 'Emerald' green, dark or cobalt blue, a deep blue-green and Persian or 'peacock' blue are most commonly associated with this period, and other colours are very rare. Of these, Emerald green and peacock blue were new colours introduced by the Romano-Italian industry and almost exclusively associated with the production of fine wares.
However, during the last thirty years of the 1st century AD there was a marked change in style, with strong colours disappearing rapidly, replaced by 'aqua' and true colourless glasses. Colourless and 'aqua' glasses had been in use for vessels and some mosaic designs prior to this, but start to dominate the blown glass market at this time. The use of strong colours in cast glass died out during this period, with colourless or 'aqua' glasses dominating the last class of cast vessels to be produced in quantity, as mould and free-blowing took over during the 1st century AD.
From around 70 AD colourless glass becomes the predominant material for fine wares, and the cheaper glasses move towards pale shades of blue, green, and yellow. Debate continues whether this change in fashion indicates a change in attitude that placed glass as individual material of merit no longer required to imitate precious stones, ceramics, or metal, or whether the shift to colourless glass indicated an attempt to mimic highly prized rock crystal. Pliny's Natural History states that "the most highly valued glass is colourless and transparent, as closely as possible resembling rock crystal", which is thought to support this last position, as is evidence for the persistence of casting as a production technique, which produced the thickly walled vessels necessary to take the pressure of extensive cutting and polishing associated with crystal working.