What is the aspect of inimitability and eloquence in likening the wide-eyed houris to "ruby and coral" in Surat Ar-Rahman, given that ruby and coral are opposite in their physical properties yet similar in their beauty?

Ibn Ashour likens the women of Paradise to rubies and coral due to their beautiful red color, and their purity and luminosity. Al-Qurtubi also mentioned that their transparency and beauty are such that the whiteness of their shins and marrow can be seen from behind seventy garments. This is based on the verse, "As if they were rubies and coral," and it is also said that red drink can be seen through white glass.