My understanding is that suiseki, in the formal sense, are representative of natural scenes—mountains, waterfalls, etc.—with the occasional thatched hut or animal figure. IMO, viewing stones consist first of a stone that has meaning for its owner. For you, that stone is a remembrance of a particular moment and place, and thus valuable, even if only to you.
You might also consider displaying it on a small suiban, or even one of the rectangular trays that come with small Chinese pots, resting on a bed of sand. There is a fine, pure black sand that you can find at aquarium stores or craft stores. I did this with a brown waterfall stone about the size of my fist, that I found in Alaska. In a reddish brown tray, the black sand makes the brown and cream colors in the stone pop out visually. If you mist the sand with a spray bottle, you can get an incredibly smooth, flat surface for the sand using an ordinary paint brush.
Cool find.