وَتُضِيءُ فِي وَجْهِ الظَّلَامِ مُنِيرَةً كَجُمَانَةِ الْبَحْرِيِّ سُلَّ نِظَامُهَا
Against the darkness she shines like a sea pearl taken from its string.
Tuḍīʾu describes brightness. The image ka-jumānat al-baḥriyyi likens the pale animal to a sea pearl, sulla niẓāmuhā meaning removed from its string.
The “face of darkness” personifies night; against it the animal’s brightness becomes especially striking. The simile depends on contrast in color and visibility.