I’ve always wanted to play from an earthy, organic, toesplanted-in-the-soil place,” says guitarist Gary Clark Jr., who is singlehandedly taking the blues into the future. Influenced by rock, soul, and hip-hop as much as by the Mississippi Delta blues, Clark, 28, started performing at age 14 in clubs in his native Austin, Texas. Alicia Keys has compared him to Jimi Hendrix and Marvin Gaye. Eric Clapton invited him to play at his 2010 Crossroads concert. Last February, Clark performed at the White House with B. B. King, Mick Jagger, Jeff Beck, and Buddy Guy for President Obama. And Jay-Z booked him for the recent two-day Made in America festival. Now, with the release of his first full-length album, Blak and Blu, Clark talks to Lisa Robinson about his influences, guitars,…