Valmiki Ramayana Kishkindha Kanda Sarga 40 Shloka 62
Original Shlokaकाञ्चनस्य च शैलस्य सूर्यस्य च महात्मनः।।4.40.62।। आविष्टा तेजसा सन्ध्या पूर्वा रक्ता प्रकाशते।
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काञ्चनस्य of the golden, शैलस्य mountain's, महात्मनः of the great, सूर्यस्य च and Sun's, तेजसा with brightness, आविष्टा filled, पूर्वा सन्ध्या early morning twilight, रक्ता red in colour, प्रकाशते will be glowing.
'The early morning twilight appears bright red because of the glow of the golden mountain as well as of the great Sungod.