The word(s) "grey" appears 3 time(s) in 3 verse(s) in Quran in Muhammad Pickthal translation.

(1) Saying: My Lord! Lo! the bones of me wax feeble and my head is shining with grey hair, and I have never been unblest in prayer to Thee, my Lord.

(سورة مريم, Maryam, Chapter #19, Verse #4)
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(2) Allah is He Who shaped you out of weakness, then appointed after weakness strength, then, after strength, appointed weakness and grey hair. He createth what He will. He is the Knower, the Mighty.

(سورة الروم, Ar-Room, Chapter #30, Verse #54)
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(3) Then how, if ye disbelieve, will ye protect yourselves upon the day which will turn children grey,

(سورة المزمل, Al-Muzzammil, Chapter #73, Verse #17)
(Arabic, Transliteration, Urdu (Ahmed Ali), Urdu (Jalandhry), Farsi, Yusuf Ali, Shakir, Picthal, Mohsin Khan, French, Spanish, Indonesian, Malay, German, Bosnian, Russian, Dutch, Italian, Portuguese, Tafsir - Jalal ad-Din, Tafsir - King Fahad Quran Complex)