Industrial minerals and rocks are those which are economically important because of desirable physical and/or chemical properties rather than metal or energy content. The evaluation of these resources for investment purposes in general follows established procedures after due consideration of well documented input data. However, in view of the sensitivity of many industrial mineral projects to specific inputs they require very careful analysis._x000D_
The characteristics of the industrial minerals and the industrial minerals industry are reviewed and the significance of logistics, customer requirements, technology and marketing are discussed. Implications in relation to resources/reserves terminology are considered with phosphate rock used as an example._x000D_
It is concluded that industrial mineral projects as a consequence of technology and market dependence in particular can give a high level of investment risk. The industry, however, offers most interesting and challenging employment opportunities for geologists, mineral engineers and economists.