Materials, archaeological minerals

It seems appropriate, therefore, to begin a survey of archaeological materials with a discussion of inorganic materials - from minerals and rocks, the most abundant materials on the planet, to those extracted, derived, or made from them, such as metals and alloys, glass and ceramics (Chapters 1-7). Organic and biological materials produced by, or derived from plants or animals are discussed next (Chapters 8-15). Finally, the atmosphere and the hydrosphere, which make up most of the environment that affects all materials and determines the way they decay, are surveyed (Chapter 17). 

Zircon is often present in geological and archaeological materials. The mineral can therefore be used for dating. Templer (1985) suggested using the intense TL peak near 100 C for dating. The mineral is often found in U-rich minerals, when its TL reaches saturation imder the intense radioactivity. Under these conditions Amin and Durrani... 

Deteriora.tlon. Apart from physical damage that can result from carelessness, abuse, and vandaUsm, the main problem with metal objects Hes in thek vulnerabihty to corrosion (see Corrosion and corrosion control) (127,128). The degree of corrosion depends on the nature and age of the object. Corrosion can range from a light tarnish, which may be aesthetically disfiguring on a poHshed silver or brass artifact, to total mineralization, a condition not uncommon for archaeological material. 

North American archaeological sites reflect the use of colorants, exemplified by the abundance of die inorganic mineral pigment red ochre in domestic and mortuary contexts in sites from the Clovis through the Mississippian periods (10000 B.P.-1400 A.D.). Typically the presence of these accumulations of pigment minerals is interpreted as material used in ceramics, or for body painting. Color on textiles is not usually considered. 

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