Difference between revisions of "Glass and Amber Working"
Revision as of 17:44, 26 October 2018
Glass was used in a number of ways by the Saxons and Vikings; for drinking vessels, window glass, jewellery, enamelling and beads.
Remains of glass making furnaces have been found in York and Glastonbury. There is further evidence for glass making in Kent, Jarrow, Barking Abbey, Gloucester and Lincoln, and Bede documents glass making in England. Traces of glass working have also been found at Ribe in Denmark and Hedeby in northern Germany, although finds of glass items come from all over Europe.
There were two main ways of making glass: either from the raw materials of quartz and soda (or by the late tenth century, quartz and potash), or more usually by melting down broken glass (cullet) and then re-using it.
It goes without saying that the broken glass or cullet used had to be of the required colour or clear, so that no expensive new minerals were added to colour it. The problem of getting enough of one colour was overcome by importing blocks of coloured glass taken from continental mosaics (tesserae) and windows (so there's nothing new in recycling glass!).
Making glass from the raw materials was more difficult. The quartz generally came from clean, stone-free sand, usually river-bed sand. The soda was imported from the eastern Mediterranean in a form called natron. Potash (made by passing water through burnt wood or root vegetables), was obtained by evaporating strong alkali solutions of ash. The sand, natron or potash were then mixed together and heated in an oven for several days. The mixture was constantly raked and stirred to allow waste gasses to escape. It was then broken up and put into a crucible, often with cullet added, and melted in a furnace. If all went well glass was formed; however, the large lumps of partly formed waste glass which have been excavated, show how difficult the process could be.
When glass is made in this fashion, it is clear or has a slight green tinge. In order to colour it minerals were added; copper for red, blue or green, iron for black, tin for yellow. Coloured glass found includes pale blue, dark blue, blue-green, emerald green, olive green, amber, yellow-brown, red and black.
Glass vessels were also made, one of the commonest excavated styles being the 'claw beaker' of the pagan period. (These were actually poor representations of a common Roman glass vessel that had dolphins leaping down it's sides which then became over time more and more crude and simplified. Whilst we see them as 'claws', the Germans call them 'trunks' as in Elephant trunks.). Glass bowls are known although excavated examples are fairly uncommon. Conical drinking vessels occur during the earlier Viking period, but are by no means common, and were mostly imported from the Rhineland. This style seems to have been superseded by the bag beaker later on.
To make glass containers, the craftsman collected a blob of molten glass on the end of a hollow rod and blew into it. By careful blowing, spinning and using specialised tools and moulds, vessels of quite complicated shapes could be manufactured. Drinking glasses and bowls were sometimes decorated with trails of molten glass applied to their outer surface. Excavated finds dated to the Later Anglo-Saxon period would suggest that their glassware was getting cruder. An example of a bag-beaker from Winchester is pretty awful looking. This may be a false view due in part to the relative few finds, which seems to at odds with the general development elsewhere at that time.
Glass finger rings were popular and were made either by shaping molten glass around a metal rod of the right diameter or by placing a blob of molten glass on the point of an iron cone, which was then spun causing the glass to roll evenly down the cone until the desired size of ring was reached.
Glass was also used in jewellery in the same way as semi-precious stones. Glass playing pieces for board games have also been found in some numbers. In the later Anglo-Saxon period, glass was used modestly for some church windows. To date only blue glass seems to have been found, with the odd pieces displaying some decorative brushwork on them. Clear window glass may have been used in the homes of a few wealthy people although this is not certain.
One of the commonest uses for glass was as beads. The glass for these often had lead oxide added to give the beads extra sparkle. It also made the material easier to work as it lowered the melting temperature. Glass beads were made by using a 'pontil' rod to pick a blob of molten glass from a crucible. Tongs were then used to form a globular bead, or by using other tools to form other shapes.
Some shapes were made by rolling the bead on a smooth marble block whilst the glass was still soft. The beads were left plain or decorated with blobs or trails of a different coloured glass. These could be left raised, or pressed right in to produce a smooth bead. Some of the Scandinavian glass beads were very colourful with a mosaic pattern of glass (called 'millefiori', meaning thousands of flowers) applied to the surface of the bead. This effect was achieved by a series of quite complex actions.
Each different pattern was obtained by fusing composite coloured glass rods in varying combinations, and these rods themselves were formed by bunching and folding over others, and then drawing out the hot glass into narrow rods much like seaside rock. A necklace of these beads was the product of great expertise and skill, as well as being a beautiful piece of costume jewellery.
Beads have been excavated in large numbers from early period female Viking graves. Three hundred or so is not uncommon, although these were the smaller single coloured type. In male Viking graves, the number of beads is drastically different. In the whole of the British Isles, there have been no more than three beads found in any one grave, and only five distinct positions where they were situated. These usually comprise of two at the neck, with an additional one to possibly close a garment, and two at the waist. One of these may have fastened a pouch and the other which was occasionally found as low as the knee, could have been a charm or keepsake.
The pre-Christian Anglo-Saxons were also keen on beads, in the same manner as the Vikings. However, later on in the 8th-11th centuries their use became uncommon in both sexes. It is uncertain whether this coincides with the spread of Christianity, although their flamboyant use amongst the Vikings also declined over a similar period of time. The Christian practice of burying their dead without grave goods does not assist in our interpretations. It could be that strings of beads were still worn underneath garments, however, the whole practice may also have been viewed by then as unsophisticated.
Glass is also used to produce enamel. Enamel is essentially just coloured glass ground up into a fine powder. The powder is usually placed on a bronze piece of jewellery that has a low surround. When the piece is heated up so that the glass melts, it flows to fill the area colouring it and fuses to the background. After cooling slowly, the piece is then ground to remove excess enamel, and polished. Several colours were commonly used on a piece, each in a separate 'field' to prevent the enamel from running together blurring the final piece.
It is interesting to note that the glass bead workshops found at Clifford Street in York were associated with an amber bead industry, suggesting that bead making was completely separate from the glass industry. Amber beads were made by taking a block of amber, cutting it to roughly the right shape and drilling a hole through it. Its final shape was attained by turning it on a bow lathe before polishing with coarse sand and fine powder. Wedge shaped beads were also made, and they would often be mixed on a necklace, with perhaps a wedge shaped pendant as the centre-piece.
Amber is the fossilised resin of ancient pine trees, submerged under the sea in thin veins. It can be gathered along the North Sea coasts of East Anglia, south-west Jutland and the southern shores of the Baltic. It is washed loose onto beaches from its deposits by sea currents, causing it to float to the surface, especially during violent storms. Ranging in colour from a dark, reddish brown to a translucent straw, it was a treasured material, particularly by the Vikings. Other uses for amber, apart from bead making included pendants, amulets, gaming pieces, spindle-whorls, and finger rings.
We can deduce the processes that were employed by examining the remains of discarded or lost, part worked or broken beads, for wear or tooling marks. A finger ring would require a large piece of amber. This would be cut into slices with a saw, and then shaped with a chisel until it was roughly circular. The disc was placed on a bow lathe; the outside was polished and shaped and the centre was cut out to form a ring. The centre piece could then be used to make a bead. Many half finished rings were found in York, demonstrating that the amber worker often made mistakes with this time consuming tricky process and brittle
- On Divers Arts, by Theophilus, translated by J.G.Hawthorne and C.S.Smith. Dover publications. ISBN: 0-486-23784-2.
Original article by Ben Levick, 1992
Revised by Roland Williamson, 1999