Touchstone

A special Granite used for Starry Sky Divination, seemingly imbued with Incredible energy.
The number of Touchstones consumed during Starry Sky Divination gradually increases with each attempt:
1st attempt: 1
2nd attempt: 2
3rd attempt: 3
4th attempt: 5
5th attempt: 7
6th attempt: 9
7th attempt: 12
8th attempt: 15
9th attempt: 18
10th attempt: 22
11th attempt: 26
12th attempt: 30