Aurora Stone

A special Aurora Stone used for Starry Sky Divination, it seems to carry incredible energy.
The number of Aurora Stones consumed during Starry Sky Divination increases progressively with each attempt:
1st time: 1 piece
2nd time: 2 pieces
3rd time: 3 pieces
4th time: 5 pieces
5th time: 7 pieces
6th time: 9 pieces
7th time: 12 pieces
8th time: 15 pieces
9th time: 18 pieces
10th time: 22 pieces
11th time: 26 pieces
12th time: 30 pieces