If you’re looking for unusual one of a kind stones to wrap, I only know of two in New York City (there used to be more, and sometimes a guy pops up in Union Square selling stones) — neither of these places sells beads, though.
ROCK STAR 150 W. 28th St., Suite 301B, Manhattan 212-675-3065 This is an interesting little shop. It seems to be the hobby room of the owner, with all sorts of stones in all sorts of sizes at all sorts of prices. If you are, as I am, one who likes to browse until you find the stone which wants to become part of your creation, you might very well like this place. In my experience, the owner is most often around, and willing to chat with you about what you are looking for.
ASTRO GALLERY OF GEMS 185 Madison Ave., Manhattan 212-889-9000 This is a huge mega-stone shop. It sells large “decorator” pieces, mega collector pieces, handmade jewelry, and, also, small specimens that you could use for creating stunning wire-wrapped pieces. Don’t forget to look around downstairs (if it is open). I have felt lucky at Astro Gallery to find people who could explain to me what the properties of the particular stone I was looking at were. I say this because the place is so big, and tracking down a worker to help you can sometimes, in and of itself, be a work of art. Be that as it may, the last time I was there, they had a free print-out of metaphysical properties of a huge number of stones/crystals.