Ultra rarity is Unobtanium’s method of operation. It appears once in a block and halves after every 102,000 blocks. 196,875 Proof of Work Unobtaniums are generated before 0.0001 minimum block subsidies are affected at the 612,000th block. Zero premined coins. Unobtaniums are a SHA-256 Proof of Work coin with a three-minute block target and a 250,000 hard cap coin supply.