In studying fungi's roles in biomineralization, it has been found that fungi deposit minerals with the help of an organic matrix, such as a protein, that provides a nucleation site for the growth of biominerals. Fungal growth may produce a copper-containing mineral precipitate, such as copper carbonate produced from a mixture of (NH4)2CO3 and CuCl2. The production of the copper carbonate is produced in the presence of proteins made and secreted by the fungi. These fungal proteins that are found extracellularly aid in the size and morphology of the carbonate minerals precipitated by the fungi.