If the philosopher’s stone is nearly as good at healing as you suggest, then it’s a source of income because it’s good at healing. What else do you need?
A source of income you can use without attracting attention to your only source of income. (Otherwise, you risk losing it.) Such as, repairing objects when no one else is looking. If you buy a broken or damaged object from one person, fix it, and sell it to another person, no one needs to know you repaired it. But even if they know you repaired it, they don’t have to know you repaired it using a magical artifact.
If the philosopher’s stone is nearly as good at healing as you suggest, then it’s a source of income because it’s good at healing. What else do you need?
A source of income you can use without attracting attention to your only source of income. (Otherwise, you risk losing it.) Such as, repairing objects when no one else is looking. If you buy a broken or damaged object from one person, fix it, and sell it to another person, no one needs to know you repaired it. But even if they know you repaired it, they don’t have to know you repaired it using a magical artifact.