You will need the Master Hammer (Silver x6, Mithril x2, White Rose x4 20,000 gold and the expert hammer) to get the last Ore which is only obtainable after the main light house completion which is lengthy and I will not include here however if needed here is a walkthrough for that portion:
WARNING CONTAINS SPOILERS
The soul gem(the last gem) in particular cannot be obtained until a minimum of floor 71.
For those reading ahead I HIGHLY recommend you cut all ores using Grampy Gus and then selling all of the cut gems for a profit and keeping all of the other refined materials for building needs.
(other mining tips)
•The ladder to a new floor is NEVER on the bottom row of the floor
•The ladder is USUALLY but not always far away from every smashable rock (smash them last before leaving the floor)
•Bread purchased from the restaurant or food in general can be used to replenish hearts/energy. The following is the source I used for this guide: https://harvest-moon-light-of-hope-guide.fandom.com/wiki/Min... the harvest moon light of hope wiki