Rav Yitzchak Zilberstein shlita (Chasukei Chemed, Yoma 16a) records a question he was asked in connection with a stone chipped away from the Kosel. A non-Jew abroad had heard that placing a small stone from the Kosel under his sick wife’s pillow was a segulah to heal her and he contacted a Jew offering a substantial sum if he could obtain one for him. Unfortunately, immediately after placing the stone under her pillow, she passed away. When the Jew who supplied the stone heard this, he feared for his life and asked Rav Zilberstein what he needed to do to atone for his sin. Rav Zilberstein consulted his father-in-law, Rav Elyashiv, who was shocked to hear this serious transgression. He then ruled that the stone must be returned and glued back to its original place and that the person required serious kaparah for having violated the prohibition of לא תעשון כן לד' אלקיכם — “You shall not do so to Hashem your G-d” (Devarim 12:4).
Another instance: Rav Shmuel Rabinowitz noticed a stone from the Kosel on display at Ben Gurion airport. He wrote to the authorities demanding that they return the stolen stone so that he could reattach it to the Kosel. Ultimately, it was returned and an entire event was made out of it.
