Just what are micro-calcifications?

The tech didn't explain micro-calcifications. Instead she said, “Well, let’s first schedule you for an ultrasound and then talk about what’s in your breast tissue.” I got dressed and asked where I needed to go to schedule the ultrasound. The tech looked directly at me, took a deep breath and told me that she was going to walk me to the ultrasound and I was going to have it immediately. Wow! Ton -of -bricks moment. I asked her to please go and tell my husband why I was still being examined. She asked me to describe him and I quickly said “He’s the very handsome middle-aged gentleman with the short, gray hair named Michael.” She returned within minutes with a large smile and told me that she gave Michael the message. (It wasn't until our drive home that, upon hearing my side of the story, Michael shared that he was the only person in the waiting room, so it was easy for her to find him.)
During the ultrasound, the tech kept going over and over my breast, mumbling “I don’t see it. There’s nothing there.” There was a faint knock on the door and an elegant woman with hundreds of long braids and equally long fingers swept in saying she was the radiologist and was a bit suspicious of the new spots on my mammograms. She said they looked like micro-calcifications and explained that as we age calcium leaves our bones and finds its way to other places in our bodies. If it goes to our joints, it’s called arthritis; if it goes to our veins, it’s hardening of the arteries, and if it goes to our breasts, it’s called micro-calcifications. She further explained that many women have such spots on their mammograms, but since mine were tightly clustered, there could be some “Problem Cells.” Breathing became a problem.