An Illustrated History of Glass

01
of 07

Obsidian: Natural Volcanic Glass

Obsidian Outcrop near Kaletepe Deresi III (Turkey)
Obsidian Outcrop near Kaletepe Deresi III (Turkey). Berkay Dincer

Glass is that mysterious translucent substance of what is essentially super-heated silica sand. Although details about the history of glass and glass making are still disputed, the earliest use of glass was undoubtedly that of the natural glass called obsidian. Obsidian is a natural byproduct of volcanic eruptions and it was prized by prehistoric societies the world over for its shiny black, orange, gray or green beauty, its sharp edges, and its workability.

Obsidian was used to make stone tools at least as early as the Middle Paleolithic, at sites such as Kaletepe Deresi 3 in Turkey near an obsidian outcrop, and the Upper Paleolithic Ortvale Klde site in Georgia, where researchers believe obsidian use helps underline a difference between Neanderthal and early modern human behaviors.

By the way, lightning strikes in sandy soils also create glass, called fulgurites, which occasionally turn up in archaeological sites.

Intentional glass making involves the superheating of crushed quartzite sand to produce a hot liquid, which is then allowed to cool to the clear, hard substance you recognize when you stare out the windows in your house or drink from a glass or place flowers in a vase, but that's the next step in the evolution of glass making.

More Information

Read Obsidian, for a word or two about the prehistoric use of the material. Also, there is more to be found at the site descriptions of Kaletepe Deresi 3 and Ortvale Klde.

A Bibliography of Glass Making has been assembled for this project.

02
of 07

The Earliest Glass Material Manufacture

Faience Hippopotamus, Middle Kingdom Egypt, Louvre Museum
Faience Hippopotamus, Middle Kingdom Egypt, Louvre Museum. Rama

The first purposely manufactured glass material appears in the 4th millennium BC, in both Mesopotamia and Egypt, when heated crushed quartz was used to make glazes for ceramic vessels. The glazes are thought to have been accidental discoveries, possibly a byproduct of copper smelting or when crushed quartz was accidentally left in a ceramic kiln. Which civilization invented the process is unknown, but the trading network between the two assured that the method was transmitted quickly.

The technological leap in glass making called faience is essentially a modeling compound made of crushed quartz or silica sand, mixed with natron and salt, and fired. Although the original source of invention is currently unknown, faience was used to make jewelry throughout Egypt and Mesopotamia by the mid-4th millennium BC. Faience objects themselves, such as the cute little Middle Kingdom Egyptian [ca 2022-1650 BC] hippo illustrated in the photo, are not glazed, but rather completely man-made hand-molded objects which upon firing take on a shiny crust.

Evidence for the 4th millennium BC production of glazes and faience has also been found in Mesopotamia at sites such as Hamoukar and Tell Brak.

Sources and Further Information

Read more about faience, the substance and its construction methods. More information is also available about Hamoukar and Tell Brak.

Tite MS, Manti P, and Shortland AJ. 2007. A technological study of ancient faience from Egypt. Journal of Archaeological Science 34:1568-1583.

Additional information was gathered from the Bibliography of Glass Making, assembled for this project.

03
of 07

Natron and Glass Making

Natron Glass - Unguent Bottle - New Kingdom 18th or 19th Dynasty
Natron Glass - Unguent Bottle - New Kingdom 18th or 19th Dynasty. Claire H

The earliest forms of glasses were made from sand, fluxed (melted together) with either soda or potash. Adding a flux material to quartzite sand as it is melted controls both the heat and the viscosity of the glass as its formed. Natron, sodium carbonate 10-hydrate, (best known as an aid to mummification) was used as a flux for the production of faience and glazed steatite beads beginning at least in the early 4th millennium BC.

But, before about 500 BC, soda glasses in the Mediterranean area were primarily based on plant ash, produced in specialized locations in Egypt and Mesopotamia. During the 5th century BC, natron glass--glass made with soda-rich salt called natron combined with quartz sand--became dominant in the Mediterranean and Europe, and remained dominant until between AD 833 and 848, when an abrupt end came to the use of natron as a flux and glass makers in the Islamic and European markets switched back to plant ash.

What happened? In a 2006 article, Shortland and colleagues argue convincingly that the end of natron as a resource for glass making occurred when shifting politics in the region cut off the nearly universal access to Wadi Natrun.

Sources

Degryse P, and Schneider J. 2008. Pliny the Elder and Sr-Nd isotopes: tracing the provenance of raw materials for Roman glass production. Journal of Archaeological Science 35(7):1993-2000.

Kato N, Nakai I, and Shindo Y. 2009. Change in chemical composition of early Islamic glass excavated in Raya,Sinai Peninsula, Egypt: on-site analyses using a portable X-ray fluorescence spectrometer. Journal of Archaeological Science 36(8):1698-1707.

Kato N, Nakai I, and Shindo Y. 2010. Transitions in Islamic plant-ash glass vessels: on-site chemical analyses conducted at the Raya/al-Tur area on the Sinai Peninsula in Egypt. Journal of Archaeological Science 37(7):1381-1395.

Shortland A, Schachner L, Freestone I, and Tite M. 2006. Natron as a flux in the early vitreous materials industry: sources, beginnings and reasons for decline. Journal of Archaeological Science 33(4):521-530.

04
of 07

Molded Glass

Glass Production and Trade around the Mediterranean in the Late Bronze Age
Map showing glass production and trade around the Mediterranean in the Late Bronze Age. © Science

The making of molded or cast glass vessels or objects was first achieved between about 1650 and 1500 BC, probably in Mesopotamia. Glass may have been brought into Egypt after Tuthmosis III campaigned in the Levant. Glass workshops dated to the Late Bronze Age include sites such as Amarna and Malkata (14th century BC); Qantir/Piramesses (13th century); and possibly Lisht (13th-12th century).

Documentary evidence for controlled production of glass includes offertory lists on Egyptian temples such as Karnak and a mention in the Amarna letters. Glass-making processes were detailed in Mesopotamian cuneiform texts discovered in Nineveh, as part of the Library of King Assurbanipal [668-627 BC].

A primary glass work shop was discovered recently at Piramesses, Egypt; other workshops of the period have been discovered at Amarna. Also of interest is the deposit of molded ingots of glass discovered in the Bronze Age shipwreck called Uluburun.

Sources and Further Information

Duckworth CN. 2012. Imitation, Artificiality and Creation: the Colour and Perception of the Earliest Glass in New Kingdom Egypt. Cambridge Archaeological Journal 22(03):309-327.

Rehren T, and Pusch EB. 2005. Late Bronze Age Glass Production at Qantir-Piramesses, Egypt. Science 308:1756-1758.

Shortland A, Rogers N, and Eremin K. 2007. Trace element discriminants between Egyptian and Mesopotamian Late Bronze Age glasses. Journal of Archaeological Science 34:781-789.

Shortland AJ. 2007. Who were the glassmakers? Status, theory and method in mid-second millennium glass production. Oxford Journal of Archaeology 26(3):261-274.

05
of 07

Blown Glass and the Levantine Coast

Blown Glass Bottle from Sidon (Lebanon)
Blown Glass Bottle from Sidon (Lebanon). M.L Nguyen

Using human breath to modify glass, by blowing through a pipe into super-heated material, is called glassblowing. Glassblowing was developed along the Mediterranean coast of Syria and Palestine and then brought to Roman Italy during the 1st century BC. Pliny reported that glassblowing was a technique invented by the artisans of Sidon, in what is now coastal Lebanon.

By the first century AD, commercial workshops were producing blown glass vessels and window panes at Sentinum (in what is now Italy), Aix-en-Provence (France) and Bet She'an (Israel). Many Sidon glassworkers set up workshops in Roman cities such as Aquileia and Campania.

Sources and Further Information

Verità M, Renier A, and Zecchin S. 2002. Chemical analyses of ancient glass findings excavated in the Venetian lagoon. Journal of Cultural Heritage 3:261-271.

06
of 07

Roman Glass Making

Roman Glass Display, Bristol Museum (UK)
Roman Glass Display, Bristol Museum (UK). Andrew Eason

The coastal Levantine glass makers set up workshops in Aquileia and Campania and worked together with Roman artisans to perfect the glass blowing technique, eventually devising specialized equipment such as iron blow pipes and sophisticated horizontal kilns.

The blown glass technique was enhanced under Caesar Augustus and was soon spread throughout the known world. The city of Alexandria was said to have had an extensive glass industry during the Hellenistic period, as did the port of Taposiris Magna. Investigations into the chemical makeup of Roman glasses made from natron suggests that the production of ingots may have been separate from the production of the final glass product.

Quantities of Roman period glass fragments were found in the wreck of the Roman corbita Iulia Felix. The ship, which sank off the coast of Italy sometime between AD 150 and 250, is thought to have been taking broken glass intended for recycling at the workshops at Aquileia.

Sources and Further Information

Degryse P, and Schneider J. 2008. Pliny the Elder and Sr-Nd isotopes: tracing the provenance of raw materials for Roman glass production. Journal of Archaeological Science 35(7):1993-2000.

Paynter S. 2006. Analyses of colourless Roman glass from Binchester, County Durham. Journal of Archaeological Science 33:1037-1047.

Silvestri A, Molin G, and Salviulo G. 2008. The colourless glass of Iulia Felix. Journal of Archaeological Science 35(2):331-341.

07
of 07

Opaque Glass at the Venetian Lagoon

Stone, Glass, and Gold Leaf Mosaic, Church of Santa Maria della Assunta, Torcello Italy
Stone, glass and gold leaf mosaic head of an Apostle. Church of Santa Maria Assunta Torcello Italy made about 1075-1100 CE, restored in the 1100s and 1800s. Photo by Mary Harrsch

The beginning of the first truly commercial artisanship of glass making was in Roman Italy, arising from the combined talents of Levantine and Roman workers in workshops such as Aquileia. However, the Levantine coast continued to be at the forefront of glass innovation for the next thousand years.

One technique invented by the Levantine glassmakers was a recipe for opaque glass. The earliest forms of glass were transparent and colored various shades of blue green. The recipe for clear glass was created in the Roman/Levantine workshops. Opaque glasses, which allow for a greater range of color, were achieved by the Levantines. Although long believed to have been invented within the workshops of the Venetian lagoon, recent investigations at the site of Torcello suggest that the opaque glasses used in the mosaics of the Santa Maria Assunta Basilica illustrated in the photograph were not created in Torcello, but rather imported as raw glass and reworked in the workshop there.

It wasn't until about the 12th and 13th centuries AD when glass makers in Venice learned the secret and transformed their recipes from the natron-based Roman clear techniques to opaque techniques invented in the Levant, based on soda-ash.

Sources and Further Information

Stern EM. 1999. Roman Glassblowing in a Cultural Context. American Journal of Archaeology 103(3):441-484.

Verità M, Renier A, and Zecchin S. 2002. Chemical analyses of ancient glass findings excavated in the Venetian lagoon. Journal of Cultural Heritage 3:261–271.