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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| History of glass | 1/5 | https://en.wikipedia.org/wiki/History_of_glass | reference | science, encyclopedia | 2026-05-05T03:59:48.666461+00:00 | kb-cron |
The history of glass-making dates back to at least 3,600 years ago in Mesopotamia. However, most writers claim that they may have been producing copies of glass objects from Egypt. Other archaeological evidence suggests that the first true glass was made in coastal east Syria, Mesopotamia or Egypt. The earliest known glass objects, of the mid 2,000 BCE, were beads, perhaps initially created as the accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing. Glass products remained a luxury until the disasters that overtook the late Bronze Age civilizations seemingly brought glass-making to a halt. Development of glass technology in India may have begun in 1,730 BCE. From across the former Roman Empire, archaeologists have recovered glass objects that were used in domestic, industrial and funerary contexts. Anglo-Saxon glass has been found across England during archaeological excavations of both settlement and cemetery sites. Glass in the Anglo-Saxon period was used in the manufacture of a range of objects, including vessels, beads, windows, and was even used in jewellery.
== Origins ==
Naturally occurring glass, especially the volcanic glass obsidian, has been used by many Stone Age societies across the globe for the production of sharp cutting tools and, due to its limited source areas, was extensively traded. But in general, archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or ancient Egypt. A lump of glass was found at Eridu in Iraq that can be dated to the twenty-first century BCE or even earlier; it was produced during the Akkadian Empire or the early Ur III period. The glass is of blue colour, which was achieved with cobalt. Such glass is generally known as Egyptian blue, but the technique was attested in Eridu long before it emerged in Egypt. Because of Egypt's favorable environment for preservation, the majority of well-studied early glass is found there, although some of this is likely to have been imported. The earliest known glass objects, of the mid-third millennium BCE, were beads, perhaps initially created as accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing. During the Late Bronze Age in Egypt (e.g., the Ahhotep "Treasure") and Western Asia (e.g., Megiddo), there was a rapid growth in glassmaking technology. Archaeological finds from this period include colored glass ingots, vessels (often colored and shaped in imitation of highly prized hardstone carvings in semi-precious stones) and the ubiquitous beads. The alkali of Syrian and Egyptian glass was soda ash (sodium carbonate), which can be extracted from the ashes of many plants, notably halophile seashore plants like saltwort. The latest vessels were 'core-formed', produced by winding a ductile rope of glass around a shaped core of sand and clay over a metal rod, then fusing it by reheating it several times. Threads of thin glass of different colors made with admixtures of oxides were subsequently wound around these to create patterns, which could be drawn into festoons by using metal raking tools. The vessel would then be rolled smooth (marvered) on a slab in order to press the decorative threads into its body. Handles and feet were applied separately. The rod was subsequently allowed to cool as the glass slowly annealed and was eventually removed from the center of the vessel, after which the core material was scraped out. Glass shapes for inlays were also often created in moulds. Much of early glass production, however, relied on grinding techniques borrowed from stone working. This meant that the glass was ground and carved in a cold state. By the 15th century BCE, extensive glass production was occurring in Western Asia, Crete, and Egypt; and the Mycenaean Greek term 𐀓𐀷𐀜𐀺𐀒𐀂, ku-wa-no-wo-ko-i, meaning "workers of lapis lazuli and glass" (written in Linear b syllabic script) is attested. It is thought that the techniques and recipes required for the initial fusing of glass from raw materials were a closely guarded technological secret reserved for the large palace industries of powerful states. Glass workers in other areas therefore relied on imports of preformed glass, often in the form of cast ingots such as those found on the Ulu Burun shipwreck off the coast of modern Turkey.
Glass remained a luxury material, and the disasters that overtook Late Bronze Age civilizations seemed to have brought glass-making to a halt. It picked up again in its former sites, Syria and Cyprus, in the 9th century BCE, when the techniques for making colorless glass were discovered. The first glassmaking "manual" dates back to ca. 650 BCE. Instructions on how to make glass are contained in cuneiform tablets discovered in the library of the Assyrian king Ashurbanipal. In Egypt, glass-making did not revive until it was reintroduced in Ptolemaic Alexandria. Core-formed vessels and beads were still widely produced, but other techniques came to the fore with experimentation and technological advancements. During the Hellenistic period many new techniques of glass production were introduced and glass began to be used to make larger pieces, notably table wares. Techniques developed during this period include 'slumping' viscous (but not fully molten) glass over a mould in order to form a dish and 'millefiori' (meaning 'thousand flowers') technique, where canes of multicolored glass were sliced and the slices arranged together and fused in a mould to create a mosaic-like effect. It was also during this period that colorless or decolored glass began to be prized and methods for achieving this effect were investigated more fully. According to Pliny the Elder, Phoenician traders were the first to stumble upon glass manufacturing techniques at the site of the Belus River. Georgius Agricola, in De re metallica, reported a traditional serendipitous "discovery" tale of familiar type: