C36
The rock selected by Moulin Lay, in a undulating form, is called "tinea durum" or "psoriasis".
Most of the ores had tinea durum. Even if they would give out green, most of them would be devoured by the tinea. In the end, they wouldn't even be able to make a normal ring, so it could be said that they had no value at all!
Therefore, when everyone saw this ore, they could not help but sigh