Silica is the light pole in the minerals. It is a kind of flowering process in the mineral realm since silica in plant growth enhances the refined properties that light brings to plants. Photosynthesis requires light for its action. The light interacts with the flavonoids (phenols and tannins) and anthocyanins (blue and red pigments that protect tissues from too much light) as plant pigments on the periphery of the growing plant. The pigments in the skins and leaves absorb and transform the light into energies that create growth. As a plant matures the silica forces tend to collect in the part of the plant that is approaching flowering and fruiting. These are cosmic forces because of the predominance of light in siliceous materials. The cosmic pole is the light pole. These forces tend to limit vigor and enhance flavonoid production.
Sandy soil then enhances the refining process in plants that accompany fruit production. Making preparations out of silica (horn silica) and other silicates (amethyst for instance) is a way to bring enhanced light forces into the photosynthetic process in the plants. The preparation that would move in this direction is horn silica
Clay is a balancing agent in the mineral realm. It is a silicate but it also is rich in alumina. Alumina is an amphoteric metal. That means that it works to aid the solubility of silica and lime into each other. In this way clay builds a bridge to colloidal humus formation. We could say that this is moving towards the shadow pole instead of the light pole present in sandy soils. The preparation that would move in this direction is horn manure. These are the earthly forces since clay, humus, manure and such materials promote vigor.