A large percentage of the Player base are/were DF Players.
I disagree with Casiterite as a Curio as that simply IS the chief Tin ore mineral, another mineral would be more appropriate.
In any case I like the idea of vein specific Curios a lot, it piggybacks on the existing vein rarity and quality to give variety to the resulting Curios. Also my thread on Gem mining last world would be a great for Curios as well, with Pearls now serving a dual role as both Jewelry ingredient and Curio it would be entirely consistent with whats already present.