What type of rock is best?
Feeding poor soil with mixed rock dust may be compared to feeding an ill person a varied diet of unrefined, natural food. If no one single food is a panacea, it might follow that no single rock type is “ideal.” Indeed, the virtue of glacial gravel is said to lie in its broad spectrum of rock types. The late John Hamaker advocated the use of glacial gravel dust, ideally followed by river and seashore gravels and mixtures of single rock types. In the book The Survival of Civilization, John Hamaker suggests finely-ground glacial gravel because that is nature’s way throughout millennia to create fertile soils. Glacial gravel, which is a natural mixture of rocks, will create a broad spectrum of minerals in the soil in a natural balance. Much of value can also be gleaned from Europe and the research and experiences there where single rock types and combinations of single rock types such as basalt are used. Hamaker asserts that “Micro-organisms select what they need to make the compounds of l
