Flash, gleam, glance, glint, sparkle, glitter, glisten, scintillate, coruscate, twinkle mean to shoot forth light (as in rays or sparks).
Flash implies a sudden and transient outburst of light or a sudden display of something that brilliantly reflects light or seems lighted up.
Gleam implies a ray which shines through an intervening medium or against a background of relative darkness.
Glance implies darting or obliquely reflected light; glint implies quickly glancing or gleaming light.
Sparkle suggests quick, bright, brief, and innumerable small flashes of light; glitter connotes greater brilliancy or showiness than sparkle, sometimes with the implication of something sinister.
Glisten implies a more or less subdued sparkle, glitter, or gleaming that suggests the lustrous shining quality of a moist surface.
Scintillate implies the emission of sparks in a steady stream or a sparkling suggestive of such an emission; coruscate the emission of a brilliant flash or succession of flashes; both words have extended as well as literal use.
Twinkle suggests a soft and intermittent sparkling, often wavering and lustrous.