Now that we can make jewelry (if we have Crystal Creations), it's possible to give Sims their birthstones, if you have Seasons. The traditional correspondence is this: January - garnet February -...
I am amazed at how detailed some of you work things out. I admire that. Problem is I can't remember in which season my sims were born. (or in which season they were created in CAS?) So I'll do the practical approach and just use the most useful charging effects.