The Casa Del Oro Apartments located at 2124 Rock St. in Mountain View have sold for $9.5 million, $158,333 per unit or $219 per square foot. Built in 1964, the 60-unit, 43,380-square-foot apartment complex sits on 3.5 acres of land. The property features an unique single-story construction and boasts a solar-heated swimming pool and extra large chalet-type patios. An undisclosed broker represented the buyer, Sares-Regis Group. Steve Seligman with Marcus & Millichap in Palo Alto represented the seller, an Arizona-based general partnership.