ViaStone is a unique printing paper that is made with natural stone, inorganic mineral powder and trace amounts of non-toxic resins. It is designed to be used exclusively with inkjet printers. The production of Viastone is tree-free and does not require water or toxic agents. It is also biodegradable. Some have argued that using stone to produce paper is not entirely sustainable if production is upscaled, since it requires the extraction of limestone. Still, the production of Viastone and other stone-based papers is more benign than the process of producing conventional photo printing paper. Other stone-based papers include Terraskin (watch out: awful Flash website) and Xterrane. But they don't seem to be readily available in the U.S.
The Image Shop Online has the full range of ViaStone paper.