There are two widely used Blood Group systems:
ABO system, and
Rh System
But there are other blood group systems as well!
In any of the systems, we look for the presence or absence of Antigen on the RBCs of a person. In the ABO system, there are two antigens- Antigen A and Antigen B. In the Rh system, we search for the RhD antigen.
But there are other Rh antigens. There are more than 50 Rh antigens!
Currently, we combine both systems to determine a person's blood group. A person's blood group falls into one of the eight:
A+
A-
B+
B-
AB-
AB+
O+
O-
Golden Blood indicates a rare type of blood group where there are no Rh antigens at all, not only the famous RhD antigen, but all the other Rh antigens are also absent! Hence, it is also called Rh null blood!
The term Golden doesn't indicate that it's some noble kind of blood. It only signifies its rarity! So far, only 43 people have been reported to have this rare type of blood!
Having this golden blood puts the people in a dangerous situation if they need a blood transfusion. They can't get a blood transfusion from anyone, not even from an O-negative person!