What are the chances of finding a Thunderstone in the underground in Platinum before National Dex?

Question

Google failed me.

I got the Eevee from Bebe, now I want a Jolteon.

Answer 1

There's no exact probability, but Serebii says that it is very rare before the nat. dex and uncommon after the nat. dex.
Just look for this thing.

Comments

if u want, i have a ton of t. stones and am willing 2 trade.

Answer 2

I can't give you an exact number, but it's really low and aboit the same as all the other stones. You're probably better off just getting one in a trade.