Chemical Properties

Abstract

Gathered here are those chemical properties which are not covered under the general headings of phase equilibria and crystal structure. The chemical properties of a feldspar can be considered from many viewpoints: thus, a crystal chemist emphasizes the chemical bonding, whereas a geochemist emphasizes the geochemical and petrological affinities. Ideally, each feldspar would be characterized by its content of all 90 naturally-occurring elements; the distribution of these elements among the sites of the crystal structure; the valence state; and the isotopic distribution. In chemically zoned specimens (Sec. 17.3), the spatial distribution is also important. For various reasons, the available data are incomplete and of variable accuracy, and caution is needed.