I think it's great to find sources of gems that your nation isn't strong in. They taste great, and can be used to make great hot sauces.
It is somewhat frustrating to get huge incomes of some gem type that dwarfs what your nation is _supposed_ to have. Water nations that can't find any water, Astral nations who can't find astral, etc - those are the two which have the best chance of finding "alien" gem income, what with Voice of Tiamat and Akashic Record.
Still - path boosters and/or empowerment, or summonings, can really let you take advantage of those gems (especially via Spectres, Lamia Queens, and Couatls).
And, they do make great hot sauce. Nothing like a little Nature in your Picante Verde, and Astral gives a very nice citrus sparkle to the flavors even if it doesn't have the habanero heat of Fire or Death.
