In my article Voodoo Jewelry I give some insight into the design and purpose of the voodoo jewelry sold at Erzulie's in the French Quarter of New Orleans.
If you are looking for Halloween items that are a bit more in the mainstream check out Neiman Marcus' Christmas catalog. On page 23 Neiman's offers skull and crossbones items made with jet black and clear Swarovski crystals. Of course, the items are pricey - the cheapest is the pill case at $170.
You can also view these items online.