Aventurine

Aventurine, also known as a love stone, was a variety of quartz that glitters when viewed from certain angles due to mica inclusions.

Description
This semi-precious stone could be medium to light green, dark to pale blue, or a beautiful sparkling shade of gold. Faceting only detracted from the flash below the surface of this translucent stone, so it was tumbled smooth, cut cabochon, or used as an inlay. Large deposits of aventurine with 20 lb (9 kg) blocks were not uncommon. A typical stone had a base value of 50 gp.