Interesting question. I would say yes it has different properties because of the water taking out certain minerals and stuff. But I am no expert on the subject.
I would say look at how much the wood has changed. A strong and dense wood turned light and Styrofoam-ey by the sea obviously wouldn't encapsulate strength and sturdiness quite like it did before.
Driftwood itself also has it's own properties, driftwood having been what the first Man and Woman were made from in Norse myth.
I agree with Chiron's idea. How much has the texture and the appearance of the wood changed? If it has changed drastically, as Chiron said, it obviously would not encompass the aspects it used to before being changed by the water.
Water itself promotes the emotions, cleansing, change in direction, etc. Take a look how the properties of water have influenced the wood- can the water have passed on similar properties to the wood?
This had me curious myself, so here's what I found through a bit of quick research:
''While each tree celebrates its own unique magickal qualities, when wood becomes enveloped in waters ebb and flow, its original properties and form become altered by the additions of other multiple energies it then encounters. The wood absorbs the new energies from life sources which are also housed within the water.
And too, since it no longer is restrained by roots and earth, within its newfound freedom of travel, woods magickal energy base and form is then continuously enhanced by a multitude of natural forces. Therefore, I believe it is not necessary to know the original source of a driftwoods birthright.''
Again, as Chiron also said, driftwood itself has it's own representations which you may want to look into.
I'd say that if anything, driftwood, from an aesthetic view point, would make a rather beautiful wand, especially if decorated with shells, sea glass [especially for the tip] , and maybe a sea gull feather. It would be a tool to make Neptune proud, one surging with the elemental powers of water.
I noticed everyone here spoke about sea driftwood. Some of the most beautiful driftwood I found was from a huge dam by my house..5 streams run into a gigantic dam which on the other side starts the Lehigh River in NEPA. As a matter of fact I was there today gathering driftwood for a Valhalla ladder and I found a decent size piece of absolutely beautiful driftwood. Theres hundreds of waves in it from the constant churning under the water and the best part there are 3 stems of wood that stick up and have curvature like fire wisps. This piece has to be many years old. But back to it.. not all driftwood comes from the sea so theres many other magical uses not only for water or sea witches. :-D