Silica Earth Volcanic Micronized Powder Silica Minerals, 10 lbVolcanic Silica Micronized Minerals Powder Ecologically harvested from rare mineral deposits, Silica Earth's unique profile is what makes this highly valuable to the agricultural community. The distinct typology is composed of Silicon Dioxide (SiO2), Calcium (Ca) and Magnesium (Mg) along with a broad spectrum of trace elements. Silicon is found in most native soils. However it is only available to plants in the soluble form known as monosilicic acid.