I can tell you I turned a slimline with a piece of the "unknown" wood, also. Initially I thought it was a walnut blank but once turned and finished it had a golden chatoyance that I have never seen in walnut.
It might be Koa, Chechen or a lot of other high-chatoyance woods. It would help more if you show wood in original form (cut-off will suffice, but make a picture from side and endgrain, and sand it at least 200 grit prior to photo).