My friend sent me a photo of his green star polyp. He was dipping the coral and numerous of bristle worms came out along with other types of worms and pests; loads! He asked me what these rock/sand like things are under the corals “skin.” They are very hard he said. Feel like small rocks. I thought they may be eggs but not sure. They are super tiny. They don’t look like they have any pattern. It is hard to tell. Do you guys know what these are?