Astatine consequences and lifespan:
Unlike Bedlam, Astatine is only 12% resistant to the Bayldonite and is about 35% radioactive, although just being near them does not immediately cause negative effects; its body would have to be eaten to cause harm to another creature, and it may produce rashes where it has touched someone else.
Arsenate:
A lethal dose of arsenate is about .5mg for something Astatine's size, but due to its resistance, the lethal dose of arsenate is about 0.0416mg. Because Astatine will be chronically exposed to trace amounts of arsenate, they will eventually start to suffer several symptoms:
Ingesting these trace amounts will, over time, cause: abdominal pain, salivation, vomiting, diarrhea, staggering, weaknesses, rapid and weak pulse, lethargy, low body temperature, collapse
On its face where the stone touches skin will cause: blisters, swelling, cracking, bleeding, and possibly infection
The long-term and chronic exposure will eventually lead to weight loss due to decreased appetite, and nerve damage.
Lead:
Reptiles appear to have some natural, partial resistances to lead poisoning, but still develop metallic densities in the stomach. On top of the decreased appetite and abdominal pain from the arsenate, these tiny deposits could cause further upset. Astatine may develop about one deposit every two cycles, starting after four cycles. These deposits are very tiny, and form as rounded objects that will not protrude through the stomach lining.
Timeline — 36 cycles to live
Astatine will live a life of periodic crystallization due to the chronic failure of their body.
These will happen every 4 cycles, starting when they reach 4 cycles / 7oz of weight, until their last at 36 cycles. The first cycle out of the healing chrysalis will feel refreshing, and gradually build to be horrible until its body ultimately fails each time:
1st cycle out of healing chrysalis: Refreshing, minimum symptoms, no lead deposits
2nd cycle: mild symptoms, weakness
3rd cycle: moderate symptoms, abdominal pains (lead deposits), vomiting
4th cycle: severe symptoms, take your pick
Upon entering its last chrysalis at 36 cycles, Astatine's magic will deem the stone unable to be saved, and will no longer put forth the effort into healing Astatine every 4 cycles. It will die in its chrysalis peacefully and unaware of its passing.
@Astatine