In ACNL I have got a couple of pieces of the gold funiture series which I made by bringing Cyrus a gold ore and 10,000 bells. Is this only possible to do with gold ore? Also is it possible to refurbish an item of funiture with other types of ore? For instance make a normal table an emerald table.
All ore can create customized furniture (this is it's primary function), however only very few furniture sets or items can be customized. The Animal Crossing Wikia site has a full list