Most of the wealth of persons and nations is in the form of intangible capital, much of which may be termed spiritual capital. In this chapter, the nature and definition of spiritual capital are considered and the relationship of spiritual capital to religious capital is discussed. It will be argued that the new appreciation (i) of natural capital over produced wealth and (ii) of intangible (including spiritual capital) over tangible capital will foster an alliance that will promote an ethical approach to earth and will be of benefit to all. This alliance will also be fostered by the increasing concern over the future of earth that is emanating from new secular eco-spiritualities and from the greening of religions. Eco-spiritualities are facilitating a rediscovery of an earlier reverence for nature that was lost during the centuries of colonial expansion and industrial development.