A seashell shines at Episcopal cathedral

Forget crosses, saints, and scenes from the Bible. The prominent face of a cathedral should be adorned these days with something more welcoming to all people: a seashell.

That logic has given rise to a bold new look for the front of the Episcopal Cathedral Church of St. Paul, which overlooks Boston Common. Since May, a giant aluminum sculpture depicting the cross section of a chambered nautilus with a brilliant blue background has been lighting up the pediment and turning heads at one of Boston’s busiest corners.

It’s also igniting debate about what’s lost and gained when a church uses its high-profile facade to display an ambiguous symbol rather than recognizable religious imagery.