Publisher's Synopsis
The volume is entirely devoted to the natural occurence of thorium minerals. The main part describes the 29 known silicates of thorium and covers in detail the following topics: - occurence, especially the paragenesis and processes of formation; - chemistry, with complete analyses and discussion of formula and isomorphic replacement, especially in relation to the processes of formation; - crystal form and structure; - physical properties, especially the optical properties; - chemical and thermal behavior. It soon becomes obvious that the chemical formulas of the thorium silicates are not as simple as usually given in textbooks. Structurally, the nesosilicates predominate with 9 specimens. There are 4 sorosilicates, 5 cyclosilicates, and 11 unclassified specimens. The second part is an overview on deposits of thorium comprising classification and types of deposits, a short description of individual deposits (arranged by continent and country), and some data on resources, availability, production, and prices. There are only a few deposits that are capable of being exploited for thorium as the main product, whereas by-product thorium can be obtained from a number of deposits, especially those worked for rare earth elements and/or uranium.
