Sterling silver necklace with heart pendant

I lost my sterling silver necklace yesterday around 3pm. It's an 18-inch chain with a small heart pendant, and the back is engraved with 'R.L.' in neat letters; there's a tiny blue gemstone on the heart that catches the light. I think I had it after leaving the Tyson Events Center area on 4th Street, walking toward Main Street; I retraced my steps along the sidewalk but couldn't find it. This necklace means a lot to me—it was a gift from my grandmother—and I'm really hoping someone picked it up or found it nearby. If you found it near downtown Sioux City, please drop me a message; I’d be forever grateful.