Ores, Herbs, and other such things follow only the star system up to 5 star ★, but they have a different thing called purity included, lower purity things can be refined into higher purity things by burning away impurities in the material
Example:
50 lbs of Iron ore of one ★ with a purity of 25%, to get 50% purity it will cost 25% of the current 50 lbs of Iron, leaving 25 lbs of 50% purity Iron, to get 75% purity you need to burn off 10% of the 25 lbs, that leaves 23 lbs of Iron (it's 23.5 but give me a break, remembering the .5 every time is going to get exhausting FAST for all of us), to gain 100% purity from the Iron you will need to burn off 5% of the 23 pounds of iron leaving 21 lbs left.
As you can see raising the purity to ores is a very difficult thing and doesn't give much back in its raw form, that's where purity levels when forging an alloying comes into play
25% purity gives base damage
50% purity adds a 1.5x multiplier to durability and damage
75% purity adds a 2.0x multiplier to durability and damage
100% purity adds a 2.5 multiplier to durability and damage
Alloying is only possible when an ore has 100% purity, alloying will also always produce a product at a star above the current star level of both alloys(if at the same star level, using a 1 star ore with a 2 star ore will only make a 2 star alloy), at 75% purity you can infuse mana to the ore allowing for a special bonus to be added through engraving(will be introduced in later chapters), weapons follow the star system, iron weapons will always be 1 star, if its engraved it can be a 1 star with a hollow star (hollow stars aren't actually an increase to the next grade but it's a increase in strength, proving that mana is infused increasing dmg
Ore encyclopedia:
1 star:
2 star:
3 star:
4 star:
5 star:
Herbs function slightly differently in the sense that the quality of an herb is dictated by its age, and the way it's harvested, a ten year old ginseng harvested masterfully will always be at a 100% purity, if you damage it slightly that purity drops to 75% with zero chance to raise it, unless you're an elf.
Herb encyclopedia:
1 star:
2 star:
3 star:
4 star:
5 star: