EnviroSAND is a stabilized joint sand for interlocking paving stones, cobblestone, or brick. The product is made from a combination of traditional joint sand and organic glue that forms an adhesive gel whenever it comes in contact with water. The product is formulated so that it experiences only minimal material loss in a torrential downpour. Cost: $25 per bag.EnviroBOND. 866-636-8476.www.envirobond.com.