Leonardite is a mineral originated from organic matter decomposition during the Paleozoic Era. It basically consists of charred and fossilized vegetation, high in humic and fulvic acids, among other elements such as iron and potassium. Leonardite is fundamentally one of the known types of zeolites, and as such it has a structure able to retain moisture for prolonged periods of time.

The color of a leonardite can vary from light to dark gray, depending on the origin of the deposit. Also it is usually mixed with vegetable charcoal in order to enrich soil qualities, turning it into a blackish powder.

As all minerals, leonardite is a low-solubility mined; however, the finer the particles the faster they will be dissolved into soil, provided there are suitable temperature and humidity conditions. That is why this product is handled only in superfine mesh.