In 1977 a close cooperation with the family-owned company Omya AG began. Omya AG was a global market leader in processing of calcite marble fillers and pigments. Hustad Kalk og Marmor AS was subsequently split into two companies: the raw material supplier company Hustadkalk AS, owned by the Steinsvik family, and the processing plant Hustadmarmor AS whose ownership was shared 50/50 between Hustadkalk and Omya.