The pendant is gold in color and reads "James + Loved of Family, Loved of God". Roland takes it before burying James and says that if he sees anyone that cared about the boy, if ka let him, he would give the pendant back.
The pendant protects Roland from the Little Sister's touch when they have him captive.
When put in the infirmary in the Little Sisters' Tent, Roland encounters James' brother, John Norman, who also had one of the pendants to protect himself. John's reads the same thing as James' does, except for his name.
It can be assumed everyone in the Norman family held one of these pendants.