Sorry, here's your mosaic backThis seems to have been a (careless) misunderstanding rather than a deliberate misappropriation.
By Fadi Eyadat (Haaretz)
The Israel Nature and Parks Authority recently received an unusual package in the mail from the United States - nine small bags full of white mosaic stones.
In an accompanying letter, Gail Weeks of Florida wrote that she had been touring Caesarea National Park with her husband when she picked up the mosaic tiles. Only later did they notice in their pamphlet that taking antiquities is forbidden.
Weeks also wrote that she thought there might be more stones in the sand, and asked that they tell her if anything was found.
[...]
Background here.
UPDATE (20 July): Arutz Sheva also has an article on this incident, with reference to the earlier one involving a 46 pound stone. I don't see any new information except the following:
In both cases, officials of the two agencies said, there would be no action taken against the individuals who took the items, because they were ultimately returned, and the culprits apologized.