Assertion: topaz | /r/HasAspect | low index of refraction
Facets:
value: relatively
type: DEGREE
value: for a gemstone
type: PURPOSE
Source sentences:
text: Topaz has a relatively low index of refraction for a gemstone, and so stones with large facets or tables do not sparkle as readily as stones cut from minerals with higher refractive indices, though quality colorless topaz sparkles and shows more "life" than similarly cut quartz.