Mithril Powder

Mithril Powder is a collectable that is used to upgrade Heart of the Mountain perks. It can be obtained from mining Mithril, fighting Dwarven Mines mobs, completing Events and Commissions, or from NPCs such as Fetchur and Puzzler. Two perks, Sky Mall, and Daily Powder, directly reward additional powder. The Sky Mall perk grants a chance to earn 15% extra powder for an entire skyblock day. The Daily Powder perk grants up to 1982 powder at level 100 (200 at level 1) for the first Mithril Ore mined each day, resetting at midnight Eastern Standard Time along with Fetchur. Peak of the Mountain Level 4 grants +1 Mithril Powder on every Mithril Ore you mine.

When earning mithril powder by mining blocks, there is no advantage to mining higher difficulty blocks of the same tier since all blocks within the same tier give the same amount of powder on average.