Major protein of the otoconia, a calcium carbonate structure in the saccule and utricle of the ear. Together with OTOL1, acts as a scaffold for otoconia biomineralization: sequesters calcium and forms interconnecting fibrils between otoconia that are incorporated into the calcium crystal structure. Together with OTOL1, modulates calcite crystal morphology and growth kinetics. It is unlikely that this protein has phospholipase A2 activity. . This is the function of OC90 (otoconin 90, Ensembl gene identifier ENSG00000253117).