Rhode Island is the smallest State of the U.S.A. and supposedly the only one without a single natural cave. Mineral resources are very limited, but they include granite and other stone, gemstones, sand, and gravel. There are no show caves, no show mines, and as far as we know there are no interesting subterranea which are open to the public.
That's all true, except for the part about not having a natural cave. Actually we found four, but there sure are more. There is just nothing of interest to showcaves.com.