Where would you find a lapis lazuli stone in the areas surrounding Ecclesia

Many ships that have sunk in the Kalidus channel were known to have carried lapis in their hulls. If you don't mind diving you could check there, in some common chests.

If not, the Skeleton Cave to the southeast may have chests amongst the catacombs that have lapis in them as an offering.

Though if you're against pilfering tombs, then my last recommendation would be the misty forest road leading from Wygol. Usually chests are by the road from the many carriages that have veered off of this dangerous path. The wealthy owners abandon their belongings for others to come across. Lapis may be among them.

I know as well that there is a cult of necromancers in Ruvas forest who use lapis in their rituals. Rarely, you may find a green chest emblazoned with a ruby lock. These chests commonly hold valuable possessions.

East of Ecclesia there is an old monastery, now abandoned. If you can find one of those chests there, maybe one of the priests stowed away lapis as a tribute to the dead?

Lastly -- past the Kalidus Channel -- lies Minera Prison Island. If you're not too spooked by the ghostly legends that surround the place, it's widely known that senior officers would place all their valuables in similar chests, as the prison was much more secure than their homes off base.

That's everywhere I know of, good luck in your hunt!