Diamond professionals use the grading system developed by GIA in the 1950s, which established the use of four important factors to describe and classify diamonds: Clarity, Color, Cut, and Carat Weight. These are known as the Four C s. When used together, they describe the quality of a finished diamond.
0. Most Americans adjust their clocks for Daylight Saving Time (DST) once in the spring and once in the fall -- but residents of two states, Hawaii and Arizona, have chosen not to observe it. This clocks stands in a city park in Glendale, Arizona. Wikimedia Commons. Arizona participated for one summer.
View current time in all US time zones: World Clock USA. Daylight Saving Time Since 2007: Daylight Saving Time begins for most of the United States at 2 a.m. on the second Sunday of March . Time revert to standard time at 2 a.m. on the first Sunday in November . Daylight Saving Time, for the U.S. and its territories, is NOT observed in Hawaii , American Samoa, Guam, Puerto Rico, the Virgin Islands and the state of Arizona (not the Navajo Indian Reservation, which does observe).