A temper is a non-plastic material added to clay to prevent shrinkage and cracking during drying and firing of vessels made from the clay.
Tempers may include:
*Bone;
*
Chaff;
[
*Charcoal;
*Ground ]schist
Schist ( ) is a medium-grained metamorphic rock generally derived from fine-grained sedimentary rock, like shale. It shows pronounced ''schistosity'' (named for the rock). This means that the rock is composed of mineral grains easily seen with a l ...
;
*Wood ash
Wood ash is the powder (substance), powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. It is largely composed of calcium compounds, along with other non-combustible ...
;[
*Sand or crushed ]sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
;limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
;
*Crushed igneous rock
Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
The magma can be derived from partial ...
s, such as volcanic rock
Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and me ...
, feldspar
Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagiocl ...
, or mica;[
* Grog;]fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
ized)[ (see Shell tempering in the Mississippian culture); and
*Freshwater sponge spicules.]pottery
Pottery is the process and the products of forming vessels and other objects with clay and other raw materials, which are fired at high temperatures to give them a hard and durable form. The place where such wares are made by a ''potter'' is al ...
do not require the addition of tempers. Pure kaolin clay does not require tempering.[
]
See also
Ceramic#Archaeology
Citations
References
*
*
*
* {{cite journal, format=PDF, last1=Weinstein, first1=Richard A., last2=Dumas, first2=Ashley A., title=The Spread of Shell-Tempered Ceramics along the Northern Coast of the Gulf of Mexico, journal=Southeastern Archaeology, publisher=Maney Publishing, volume=27, issue=2, pages=202–221, date=2008, url=http://www.coastalenv.com/sarc-27-02-202-221-e.pdf, accessdate=5 November 2011, url-status=dead, archive-url=https://web.archive.org/web/20120425141409/http://www.coastalenv.com/sarc-27-02-202-221-e.pdf, archive-date=25 April 2012
External links
Common Inclusions and/or Tempers
- Images (including micrographs) of shards with various tempers.
Ceramic materials