Out of them both come out pearls and Al-Marjan.pearls are well-known. As for Marjan they say it means small pearls.Mujahid, Qatadah, Abu Ruzayn, Ad-Dahhak said it, and it has also been reported from Ali.It was also said that it means large, precious pearls, this was mentioned by Ibn Jarir from some of the Salaf.Ibn Abi Hatim recorded from Ibn Abbas who said,"When it rains, the oysters in the sea open their mouths. What falls in them, the drops, turns into pearls."Its chain of narrators is Sahih.Since this type of adornment is a favor from Allah to the people of earth, He reminded them of it,فَبِأَيِّ الَاء رَبِّكُمَا تُكَذِّبَانِ