Asbestos-ceramic is a type of pottery manufactured with asbestos and clay in Finland, Karelia and more widely in Fennoscandia from around 5000 BC.
[1] Asbestos-ceramic of Lovozero ware type is also found in Fennoscandia, on Bolshoy Oleny Island in the Murmansk region of Russia.
[citation needed] From the times of the earliest comb ware (c. 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.
The fact that the reduction of iron ore (FeO3) with abundant carbon generates large amounts of carbon monoxide (CO) may suggest that the drilled holes were used to improve the availability of air (oxygen) to maintain an adequately intense flame for the high temperatures required for the iron smelting.
These ceramics were made with similar shape, size, and surface treatment (including decoration) as the asbestos pottery.
[citation needed] Hair, when used as ceramic additive, burns away at the time of firing, leaving characteristic thin pores in the resulting pottery.
However, unlike asbestos, mixing hair into clay does not improve the durability or heat resistance of the resulting ceramic.