I'm making a trip to UK and I would like to take sand from India with me as a keepsake or memento.So I was wondering if it's even worth bothering trying to bring sand aboard the plane in my carry-on?
The relevant guide says
loose soil may not be brought into the UK unless you have obtained the relevant official licence
Are you ready to debate whether sand is soil? If yes, then go ahead, otherwise I'd leave it at home.
Especially since Wikipedia on sand says
Sand can also refer to a textural class of soil or soil type; i.e. a soil containing more than 85% sand-sized particles (by mass)
so what you carry might be the organic mineral soil (which is not allowed) instead of the inorganic sand (which is allowed).