Definition of girasol

i. A name applied to many gemstones with a girasol effect, e.g. moonstone, specifically a translucent variety of 'fire opal' with reddish reflections in bright light and a faint bluish-white floating light emanating from the center of the stone.

ii. Said of any gem variety, e.g. sapphire, chrysoberyl, quartz, that exhibits a billowy, gleaming round or elongated area of light that 'floats' or moves about as the stone is turned or as the light source is moved.

iii. A name for glass spheres used in the manufacture of imitation pearls.