There is also macrocalcifications which come from other changes in the breast which is not anything they would worry about a biopsy. If it is microcalcifications and they are in clusters or grouped in a specific pattern it may signal cancer and then they would want to do a biosy or follow up mammograms.
If you are referring to Microcalcifications found within the breast tissue when a Mammogram is done, yes. They do occur normally in breast tissue and appear as tiny white dots on the film. When they are seen to be clustered or grouped in certain patterns they are cause for concern. These clusters are the reaction of breast tissue to something abnormal that is present in the breast. when they are found in clusters a Biopsy of some sort is required to ascertain the exact cause which may or may not be cancer.
Hope this addresses your concern. Regards .....