It's there, a short distance from the town to NW. It's a very small island in a middle of a very small lake. It doesn't show you the sparkles like regular items on the map do, you''ll just need to keep tapping X when you're around the right spot.BTW, had taken up the side quest where u have to find the diary of the traveller. It is supposed to be on an islqnd with two trees in the NWest of the map, but can't find it anywhere ! Any tips ?
The island really is small, with just the three trees in it and not much else. Also the water around the island is very shallow, so it really might not look like a lake at all.
Was a bit hard to spot on the world map for me too.