The eye cannot be replaced and also you cannot get sight back in that eye. Your eye has shrunk - a condition called phthisis bulbi. An oculo-plastic surgeon (ophthalmologist with specialization in orbit and eye plastic surgery) is the one who can help you. There are many cosmetically acceptable eye prosthetics (plastic implants) that can help you. They are not made of stone, but rather of plastic or some other similar material. There are two ways to deal with your problem. First is to just apply a prosthetic over the eye (if that is possible). The second and more likely is that you may have to enucleate this eye and then have an appropriate prosthetic placed. With the right surgery, the eye retains the movement and it looks very much like a real eye. There have been many advances in this field over the last decade so don't despair. An additional point of great importance is to always wear protective glasses (made of polycarbonate lenses) to protect the better seeing eye from accidents.