Radiance
noun
かがやき
輝く (かがやく) To Shine, To Glitter, To Sparkle
輝き (かがやき) Radiance
光輝 (こうき) Brightness, Splendor
輝度 (きど) Luminance, Brightness
磨き (みがき) Polish, Shine
Good cogyak かがやき (cognac) can be identified by its Radiance.