Sparkle

A child holds a piece of quartz up to the sunlight. The stone is not very valuable, but small facets catch the light and send out tiny, quick flashes – here, then there, then gone. It does not glow steadily. It dances with light. What does the quartz do? It sparkles.

Sparkle means to shine with small, quick, bright flashes, like a diamond or a star. Shine, by contrast, means to give out or reflect a continuous, steady brightness. So, sparkle focuses on broken, flickering, or twinkling light. Shine focuses on an even, unbroken glow. In other words, a diamond ring sparkles under candlelight; a polished mirror shines steadily.