Heliodor is a variety of the mineral beryl which has the chemical composition Be3Al2(SiO3)6 .
These samples are displayed in the Smithsonian Museum of Natural History.
This heliodor sample is formed with microcline and quartz. It is from Mursinka, Neyva River, Ekaterinburg, Urals, Russia. It is about 16 cm across.