Place an antique stained-glass window panel or insert in the center of your fireplace's mantel. Simply lean it against the wall. The weight of the glass will stabilize it. This is a charming alternative to a framed picture, print or mirror.
Place three small stained-glass vases of different heights and sizes at the far right side of the mantel in a cluster. You can even substitute one of the vases for a stained-glass candle holder or gas lamp.
Place one large stained-glass vase or oversized stained-glass candle holder at the far left end of the fireplace. The size of this vase will balance out the three smaller vases at the other end of the mantel without the entire presentation looking overly matchy.