theyre called the matrix or lunala. It has nothing to do with calcium, thats what most people think. It is strictly genetic if you see it or not. Its basicly the root of your nail, its not where the nail begins, the nail begins several milimeters in the finger below the cuticle but yeah its still the root of the nail. They are just nail cells that are not fully mature yet. It varies from finger to finger and it also depicts the shape of which your nail will grow. It also may dissapear as you get older.
The white half moon at the base of the nail is called the lunula.The lunula can usually be seen on the thumbs, the index finger and the middle finger, with less on the ring finger and none on the pinkie. lunula is the visible part of the nail matrix. it helps the nail to grow but it doest grow by it self . .
It helps the nail keep itself healthy kind of, so it's like a sopport and if you damage it it will damage your nail forever, I don't know why it does not grow with it, it could be because of what it does, i think it would damage the nail if it grew all over it, it would bring too much sopport?
it is not a part of thenail it is a part of skin Responsible for producing the protein keratin, which forms the nail plate