Specialized crafters with the skill and talent for it are able to cast certain spells on a gemstone to imbue them with additional effects, like granting protection, healing, elemental resistance, boosts, etc. Time varies between size, the spell, and the skill of the crafter, but most take about a day with most of it allowing the magic to settle within the stone (since no one would want it to blow up in their face). It's a common practice, so it's not difficult to find someone to learn from! The true difficulty is how well the crafter can imbue the item with the magic and keep it stable. Too much will cause the stone to shatter, too little will make it not very effective. So it would certainly take some trial and error.

As for locations, we can work out something in future quests and events, but please also make a note on your AC! If you have ideas you can submit them there, too.