The retail component of MGM Mirage's CityCenter project in Las Vegas is on schedule to open in December, officials say. However, the economic downturn forced the company to revise the lease terms for the property and assume more risk. The retail center, which is called Crystals, will include only luxury retailers who've been asked to make their CityCenter location their flagship. The building is made of glass and features jarring angles. It is scheduled to open two weeks before the central casino resort.