The Collinsville Savings Society is a handsome, squat structure of granite, brownstone and brick in the heart of the old mill village of Collinsville, Connecticut. With thick masonry walls, it’s a strongbox of architecture, a place where, unlike the transparent cubes of mostly glass that often pass for banks today, you have the feeling that your money is safe. But the exterior display of earth’s bedrock is not the only place you’ll find stone at this bank. Go to the far left teller window where you will find Lisa’s ever growing assemblage of rocks on the golden oak counter. Collected by colleagues, customers, friends, and Lisa herself, the stones sparkle in late afternoon sunlight.