When born-and-bred Texan Joanna Latham relocated to Brooklyn from Amarillo last year, she left a piece of her heart—and a pile of jewelry—behind. So the 40-year-old mother of three opened Jo Latham, a fine jewelry shop-in-shop in October 2012 inside high-end Amarillo gift store Et Cetera. The tiny outpost, which is composed of two 5-foot display cases and a corner showcase, spotlights pieces from upscale designers including Todd Reed and Nak Armstrong—brands that would otherwise be unavailable in a midsize retail ­market like Amarillo. “There’s such a talented pool of designers out there,” says Latham. “And there’s a sophisticated buyer in the area who loves having this unique offering at their ­fingertips. They don’t have to go to a bigger city and they don’t have to order from a catalog.”How did the idea for Jo Latham materialize?In 2008, out of a love of gemsto