Contemporary use of manmade stone goes back 30 years or so to the Napa Valley of California. A lightweight concrete mix using pumice as an aggregate was poured into molds cast from locally available stone. While the product was ideal for the local area, this volcanic-looking stone seemed out of place elsewhere in the country, since nobody but the West Coast had volcanoes. Over time, manufacturers sprung up around the country, using molds made from stone available in their local marketplaces. Now, manufactured substitutes are available for virtually any type of stone, and the products are generally indistinguishable from the real thing. APRIL JLC 1999 by Steve Thomas WORKING WITH Manufacture d Stone This lightweight molded concrete is indistinguishable from natural