Real, fake or in between?

Here is a question that most tribal skull collectors deal with every purchase. What is real and what is not? Let’s create a few categories:
1 – FAKE: A fake skull made of epoxy or plastic, plaster etc. Decorated like a tribal skull. Such a piece should cost no more than a few hundred euros.
2 – DECORATIVE: A real human skull, but not Papua and not even Asian, decorated with Papua or non-Papua objects such as chicken feathers. This could be a “tourist piece” from outside Asia. This should not cost more than about 1400 euros
3 – GOOD DECORATIVE PIECE: The skull is Asian and the decorations are all Papua. This could be a tourist piece from Indonesia. This should not cost more than about 2000 euros.
4 – PAPUA TRIBAL MADE PIECE: The skull is from Papua and the decorations are from Papua. The tribal piece is made in Papua. This might be a tourist piece, but from Papua. In the case of Iatmul over-modeled skulls, they may have used epoxy instead of terracotta clay. This should cost less than 3000 euros.
5 – REAL TRIBAL PIECE: This is what most collectors are always looking for. A real tribal piece, a real victim or ancestor. Feathers used here should be Cockatoo or Casuarius, not chicken. No signs of epoxy. The color of the skulls is usually white or light colored. The decoration is often very simple, even a bit boring. The prices of these skulls can be between 2500 and 5500 euros.
6 – REAL TRIBAL PIECE WITH GOOD PROVENANCE: Here’s the best deal. No explanation needed. The price can be more than 10,000 euros, but if you’re lucky you can find one for around 3,500 euros.