Wall cubes and glass vases filled with sand hold an array of seaside artifacts. Any grouping of related objects displayed on varied-height risers (or stacked books) can become a stunning fireplace focal point.
All-white vases in different sizes and shapes offer a visually united vignette for displaying fresh flowers. Or use a big vase with lush silk hydrangeas or a large potted Boston fern to decorate the space.
Leaned against the back of the fireplace box, a mirror doubles the impact of a simple arrangement of ceramic garden spheres and one twisted branch. An artistic sculpture or a unique architectural salvage piece would also work.