Assertion: agate's structure | /r/Causes | diffraction of light
Facets:
Source sentences:
text: Fire Agate is the most unique and beautiful agate to my eye, consisting of plate-like crystals of hydrated iron oxide called limonite, in iridescent opaque layers of chalcedony, with a structure that causes diffraction of light entering cabbed and polished stones, giving off a showy array of beautiful colors in unique patterns that are quite mesmerizing.