@Saxfire Edora Does say Jang is their half-brother. Plus you can see the family tree the frame just before with all the heirs connected to the same king.
@Gauvain "probably no value, because a test at "carbon 14" will show that it is a recent manufacture"
You can't use radiocarbon dating on inorganic material.
Radiocarbon dating only allows to date the time of death of a living thing.