Zinc does not occur naturally as a metal. Its ores, which do occur naturally, have a variety of different appearances. The most common ore is zinc sulfide, which is a black or brown colored rock in its natural form that glows in the dark on exposure to UV light.
Several products at Wal-Mart include zinc powder as an ingredient. Read the labels in the medicated powders section for which ones contain zinc. Raw zinc powder can be found on-line in bulk, look for Zinc Oxide Powder.
Zinc, like most transition metals is insoluble as a metal and soluble as a salt. Metalic zinc (as in an actual piece of the metal zinc) is not soluble in water. However many oxidized species are such as zinc chloride and zinc sulfate are very soluble.