Synthetic Stone

Synthetic stone is made in molds from a mixture of cement, sand and aggregate. Modern manufacturing techniques ensure that the final product looks realistic. It mimics any number of stone types — including granite and limestone — and the variety of shapes and styles includes split face, dry stacked and round river rock.

Although it's not often used to cover entire houses, it's a popular choice as an accent, covering lower portions of walls or chimney exteriors.

Upside: The look of real stone at a fraction of the cost. Lightweight, so installation doesn't require beefing up foundation footings. Synthetic stone is fire and insect resistant.

Downside: Although it costs less than real stone, synthetic stone is still one of the more expensive siding options. Discerning critics say it still doesn't look like the real thing.

Green meter: Inert material that doesn't off-gas or use toxic ingredients during manufacturing. Reduces demand for real stone and associated environmental disruption.

Cost: $12 to $25 per square foot, installed.