熠熠生辉

熠熠生辉 is high-register, common in journalism, advertising and literary writing - 'the city's lights shine brilliantly', 'the diamond sparkles', 'a rising star shines'. 熠 alone means 'glittering/dazzling'; reduplicated 熠熠 intensifies the shimmer; 生辉 = 'give off radiance'. Don't apply to plain practical light - reserve for things meant to dazzle.

Mnemonic: 熠 has 火 (fire) on the left and 习 (practice) - picture light rehearsing its dance. The double 熠熠 doubles the sparkle, then 生辉 (literally 'give-birth-to brilliance') makes the radiance bloom outward.