Though hard and durable, it can become stained, by oil in particular.
Clean granite with warm water or diluted dish soap, and dry immediately to prevent watermarks. If oil seeps in, try a nontoxic degreaser, like diluted Simple Green ($7 for 22 ounces; simplegreen.com
), or a poultice made of the cleanser and cornstarch. Coat annually with a water-based sealer.
As with marble, acidic cleaners can eat away at granite, so don't use them.