Asterism

分類:澳洲GAA學習日記
*Diasterism, such as that seen in rose quartz, is the result of light transmitted through the stone.
In order to see this effect, the stone must be illuminated from behind

*Epiasterism,Asterism seen by reflected light, as in star ruby or sapphire cut en cabochon to reveal asteria.
The effect is created when light is reflected from suitably oriented inclusions within the stone