things produced by a devil fruit are dispelled by seastone, for example the rust rust fruit wouldent be able to rust a seastone blade, perona's ghosts wouldent be able to pass through a seastone wall, in cases of parimicia the effect is negated, by that logic a construct would be negated as well, as in all forces relating to the devil fruit being enacted on it would stop working, for example a devil fruit controled puppet would have the user lose their control over it if it were touched by seastone, an object made invulnerable by a devil fruit would lose that defense, ect