Cysy Mineração Ltda, founded in 1980 in Santa Catarina (Brazil), specializes in the modern extraction and processing of fossilized marine shells to supply the agribusiness market with differentiated products such as fertilizers, agricultural lime, and oyster shell meal. Its shell-based limestone—produced by grinding fossilized marine shells—has proven agronomic efficiency supported by official Brazilian research institutions. The company’s first products were Shell Limestone and Oyster Shell Meal. In 2009, it also began producing a granulated “simple mineral fertilizer” that works as an acidity corrector and a source of soluble calcium, an essential plant nutrient. Responding to growing demand for differentiated solutions, Cysy has invested in technologies aligned with modern, sustainable agriculture. In 2013, it introduced Cysy+S, an innovative granulated shell-limestone product that combines calcium carbonate with calcium sulfate (agricultural gypsum) to improve subsoil acidity correction and provide a cost-effective source of sulfur. Cysy continues to expand through R&D, developing new calcium carbonate–based alternatives for farmers.