218 Church St., San Francisco Those who say size matters clearly haven’t visited Fiat Lux. The jewelry store, founded in 2011 by husband and wife Alexei Angelides and Marie McCarthy, is no larger than a standard walk-in closet—about 100 square feet in all. Yet miraculously, the owners have managed to imbue the Mission District space with a distinct point of view and attitude to spare. Most of the rings, necklaces, and bracelets boast geometric designs and unusually colored rocks and rare gems. “Weirdo stuff with diamonds,” McCarthy says. “The weirder, the better—that’s our game.”  The Accidental Jewelers Angelides and McCarthy didn’t set out to be jewelers. When the pair met in 2008, McCarthy owned a tattoo parlor in the Haight-Ashbury neighborhood and Angelides was a Ph.D. candidate in philosophy at Stanford University. McCarthy once owned a small jewelry store a