Here's a picture of a fireplace we made from the unused reject Dutch oak. It looked really tatty, initially, with areas of rot and fungal growth, but by the time we'd cut that out, planed it and belt sanded it, the seasoned timber looked superb. We then tastened it together with either coachbolts, or Timberlok, and dowelled the holes. Below are some other pictures of fireplaces made from new French oak.
Really beautiful, with a magnificent warm texture and grain, that enlivens the whole room