The physical structure and appearance of the bone that makes up the Starchild Skull is radically different from normal human bone. The bone of the Starchild Skull:
- Is about half as thick as comparable human bone,
- Weighs about half as much as comparable human bone,
- Is significantly harder to cut than human bone,
- Contains a reddish residue and microscopic fibers unlike anything seen before in human bone,
Slight thinning of the bone does occur naturally after death, however the image to the right shows the Starchild Skull, which is 900 years old, compared to a 900 year old normal human skull found in the same mine tunnel, so it is a true "apples to apples" comparison. Various aliments such as Hydrocephaly and Osteoporosis can cause bone to become thinner, however these conditions cause the bone to become more brittle or weaker.