Clarity: Clarity assesses the internal characteristics of the diamond as it formed in nature. This C factor is graded on a 10-grade scale and also impacts the diamond's rarity and value.
The fastest marathon ever was run by Geoffrey Mutai (2:03:02) at the Boston Marathon on April 18, 2011. But because the legendary Boston course does not meet IAAF layout standards, the World Record belongs to Patrick Makau (2:03:38) recorded at the Berlin Marathon on September 25, 2011.
Steve Edwards, a member of the 100 Marathon Club, set the world record for running 500 marathons in the fastest average finish time of 3 hours 15 minutes, at the same time becoming the first man to run 500 marathons with an official time below 3 hours 30 minutes, on 11 November 2012 at Milton Keynes, England.