Asbestos-Ceramic
Encyclopedia
Asbestos-ceramic refers to types of pottery
manufactured with asbestos
and clay
with adiabatic
behaviour in Finland
, Karelia
and Northern-Scandinavia
. A further vessel-type does not contain any asbestos, but it has insulating properties and is therefore sometimes included under asbestos-ceramic.
The most probable origin of this style of ware is the shores of lake Saimaa
in Finland which is the only place for richer easily accessible natural deposits of asbestos in its area of distribution. Finds from inland Finland are the oldest. In Finland real Asbestos-ware is known from ca. 3900–2800 BC to ca. 1800–1500 BC. In Northern-Scandinavia asbestos ware appears apparently from ca. 1500 BC to ca. 500 BC.
Asbestos ware is usually classified under Comb Ceramic ware
. From the times of the earliest comb ware (ca. 5000 BC) in Finland asbestos was mixed with clay as an adhesive. At some point people started to make use of the characteristics of asbestos: its long fibres allowed large vessels with thin walls which made them lighter without compromising durability. Some of the vessels had 6 mm thick walls with a diameter of around 50 cm (Pöljä-style). The ware is divided into the following styles (Finland):
There are two variants of asbestos-pottery depending on its asbestos amount. Asbestos pottery had an asbestos amount of 50–60%. It is usually found along evidence suggesting metal work, i.e. crucible
s, mould
s, slag
, fused clay, artefacts of bronze
and copper
and stone sledge hammers. There are a few finds of pure copper artifacts among asbestos ceramic finds. These include a bracelet and a hachet (Finland) and some pieces of copper (Sweden). Asbestos ceramic can also have been used as a heat-storage. The vessel patterns are identical to the Neolithic
and Bronze Age
Jōmon culture in Japan
(Jōmon = rope pattern). The most common patterns, however, are the comb and pit decorations typical of North-Eastern Europe at the time (Finland).
The asbestos ware refers to vessels containing 90% asbestos and 10% clay, and can resist heat up to 900–1000 °C. The clay made the shaping of vessel possible, but the high amount of asbestos does not classify it as pottery in formal sense. It is believed that the asbestos ware was used in iron production such as spearhead
s, arrowhead
s and artefact
s. The vessel is also drilled with many holes. The fact that the reduction
of iron ore (FeO3) with abundant carbon
generates large amount of carbon monoxide
(CO) may suggest that the drilled holes were used to increase the influx of air (oxygen
) required for proper glowing process. Iron ore is abundant in lakes e.g. in Finland.
Lastly, the hair-temperature pottery refers to ware made of fine, sorted clay tempered with ca 30% finely cut hair and chamotte with similar shape, size, surface treatment (including decoration) as the asbestos pottery. It does not generally contains asbestos, but some samples have small traces. Hair, when used as ceramic temper, leaves thin pores in the ware after firing. Its usage is unknown, but its adiabatic capacity suggest some kind of insulating usage (but not heat resistance).
The analysis made by University of Lund, Department of Quaternary Geology, on asbestos pottery was quite unexpected, since this part of Northern Europe, usually considered to be a step behind the rest of Europe, actually introduced iron production in the pre-Roman Iron Age.
The style seems to disappear around 200 AD in Finland but continues in Scandinavia. The disappearance is thought to be related to the transition to a semi-nomadic reindeer husbandry lifestyle.
Pottery
Pottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery . Pottery also refers to the art or craft of the potter or the manufacture of pottery...
manufactured with asbestos
Asbestos
Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...
and clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
with adiabatic
Adiabatic process
In thermodynamics, an adiabatic process or an isocaloric process is a thermodynamic process in which the net heat transfer to or from the working fluid is zero. Such a process can occur if the container of the system has thermally-insulated walls or the process happens in an extremely short time,...
behaviour in Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
, Karelia
Karelia
Karelia , the land of the Karelian peoples, is an area in Northern Europe of historical significance for Finland, Russia, and Sweden...
and Northern-Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
. A further vessel-type does not contain any asbestos, but it has insulating properties and is therefore sometimes included under asbestos-ceramic.
The most probable origin of this style of ware is the shores of lake Saimaa
Saimaa
Saimaa is a lake in southeastern Finland. At approximately , it is the largest lake in Finland, and the fourth largest in Europe. It was formed by glacial melting at the end of the Ice Age. Major towns on the lakeshore include Lappeenranta, Imatra, Savonlinna, Mikkeli, Varkaus, and Joensuu. The...
in Finland which is the only place for richer easily accessible natural deposits of asbestos in its area of distribution. Finds from inland Finland are the oldest. In Finland real Asbestos-ware is known from ca. 3900–2800 BC to ca. 1800–1500 BC. In Northern-Scandinavia asbestos ware appears apparently from ca. 1500 BC to ca. 500 BC.
Asbestos ware is usually classified under Comb Ceramic ware
Pit-Comb Ware culture
The Pit–Comb Ware culture Comb Ceramic culture was a northeast European culture of pottery-making hunter-gatherers. It existed from around 4200 BC to around 2000 BC...
. From the times of the earliest comb ware (ca. 5000 BC) in Finland asbestos was mixed with clay as an adhesive. At some point people started to make use of the characteristics of asbestos: its long fibres allowed large vessels with thin walls which made them lighter without compromising durability. Some of the vessels had 6 mm thick walls with a diameter of around 50 cm (Pöljä-style). The ware is divided into the following styles (Finland):
- early asbestos ware:
- Pit-Comb ware with asbestos
- Kaunissaari ware
- main styles:
- Pöljä ware
- Kierikki ware
- late asbestos ware:
- Jysmä ware
There are two variants of asbestos-pottery depending on its asbestos amount. Asbestos pottery had an asbestos amount of 50–60%. It is usually found along evidence suggesting metal work, i.e. crucible
Crucible
A crucible is a container used for metal, glass, and pigment production as well as a number of modern laboratory processes, which can withstand temperatures high enough to melt or otherwise alter its contents...
s, mould
Molding (process)
Molding or moulding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern....
s, slag
Slag
Slag is a partially vitreous by-product of smelting ore to separate the metal fraction from the unwanted fraction. It can usually be considered to be a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and metal atoms in the elemental form...
, fused clay, artefacts of bronze
Bronze
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...
and copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
and stone sledge hammers. There are a few finds of pure copper artifacts among asbestos ceramic finds. These include a bracelet and a hachet (Finland) and some pieces of copper (Sweden). Asbestos ceramic can also have been used as a heat-storage. The vessel patterns are identical to the Neolithic
Neolithic
The Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...
and Bronze Age
Bronze Age
The Bronze Age is a period characterized by the use of copper and its alloy bronze as the chief hard materials in the manufacture of some implements and weapons. Chronologically, it stands between the Stone Age and Iron Age...
Jōmon culture in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
(Jōmon = rope pattern). The most common patterns, however, are the comb and pit decorations typical of North-Eastern Europe at the time (Finland).
The asbestos ware refers to vessels containing 90% asbestos and 10% clay, and can resist heat up to 900–1000 °C. The clay made the shaping of vessel possible, but the high amount of asbestos does not classify it as pottery in formal sense. It is believed that the asbestos ware was used in iron production such as spearhead
Spearhead
A spearhead is the sharpened tip of a spear.Spearhead may also refer to:-Armed conflict:* Armoured spearhead, a tactical formation* Spearhead, nickname of the U.S. 3rd Armored Division in the U.S...
s, arrowhead
Arrowhead
An arrowhead is a tip, usually sharpened, added to an arrow to make it more deadly or to fulfill some special purpose. Historically arrowheads were made of stone and of organic materials; as human civilization progressed other materials were used...
s and artefact
Artifact (archaeology)
An artifact or artefact is "something made or given shape by man, such as a tool or a work of art, esp an object of archaeological interest"...
s. The vessel is also drilled with many holes. The fact that the reduction
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
of iron ore (FeO3) with abundant carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
generates large amount of carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
(CO) may suggest that the drilled holes were used to increase the influx of air (oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
) required for proper glowing process. Iron ore is abundant in lakes e.g. in Finland.
Lastly, the hair-temperature pottery refers to ware made of fine, sorted clay tempered with ca 30% finely cut hair and chamotte with similar shape, size, surface treatment (including decoration) as the asbestos pottery. It does not generally contains asbestos, but some samples have small traces. Hair, when used as ceramic temper, leaves thin pores in the ware after firing. Its usage is unknown, but its adiabatic capacity suggest some kind of insulating usage (but not heat resistance).
The analysis made by University of Lund, Department of Quaternary Geology, on asbestos pottery was quite unexpected, since this part of Northern Europe, usually considered to be a step behind the rest of Europe, actually introduced iron production in the pre-Roman Iron Age.
The style seems to disappear around 200 AD in Finland but continues in Scandinavia. The disappearance is thought to be related to the transition to a semi-nomadic reindeer husbandry lifestyle.
Source
- Hulthén, Birgitta, "On Ceramic ware in Northern Scandinavia during the Neolithic, Bronze and Early Iron Age" (1993).