Fatir 35:27
The verse joins two images within one frame: water comes down from the sky and fruits take on their colours; the one who looks to the mountains meets another series of colour — "judad" (streaks, stripes): "bīḍ" (white), "ḥumr" (red), "gharābību sūd" (jet black).
أَلَمْ تَرَ أَنَّ ٱللَّهَ أَنزَلَ مِنَ ٱلسَّمَآءِ مَآءً فَأَخْرَجْنَا بِهِۦ ثَمَرَٰتٍ مُّخْتَلِفًا أَلْوَٰنُهَا ۚ وَمِنَ ٱلْجِبَالِ جُدَدٌۢ بِيضٌ وَحُمْرٌ مُّخْتَلِفٌ أَلْوَٰنُهَا وَغَرَابِيبُ سُودٌ
Have you not seen that God sends down water from the sky? With it We produce fruits of various colors. And in the mountains are streaks of white and red—varying in their hue—and pitch-black
Fatir 35:27 · Translation: talal-itani
Image
Living colours and geological colours stand side by side, all under the same sky.
Observation
In modern geology the colour differences in mountain masses are explained by rock composition: limestone and dolomite appear white-cream, strata rich in iron oxide appear red-rust, basalt and some igneous rocks appear dark brown to black. In Arabia, Anatolia, and the Maghreb these different colour streaks can be followed on mountain surfaces with the bare eye. The language of the verse is deeply observational: not mineralogical names, but three basic colours caught by a distant eye.
Exegesis
Exegetes note that the phrase "mukhtalifun alwānuhā" (their colours different) is repeated twice: once of the fruits, once of the mountains. Al-Qurṭubī observes that this repetition points to the thought that "visible diversity emerges from a single source." Al-Rāzī conveys that "gharābīb" in Arabic names the deepest, ravenous black — how some surfaces of the mountain stand at the far end of the dark range.
Sources
Tafsīr: al-Qurṭubī · al-Jāmiʿ li-Aḥkām al-Qurʾān; al-Rāzī · Mafātīḥ al-Ghayb. Science: geology and mineralogy — standard literature on rock types and their colour components; iron oxide, limestone, basalt.