Like people, gems come in closely related families. One of the most important gem families is beryl.  With a trace of chromium to bestow a fabulous green, beryl becomes emerald, the rare and valuable green gem. If instead, nature includes a trace of iron in one valence state, beryl is aquamarine. If the iron in beryl has a different valence state, it isn’t pale blue: it turns a rich golden yellow. Golden beryl is as brilliant as aquamarine, with a warm sunny color.
Beryl is found in all corners of the globe, with individual colors being determined by the other minerals found in those regions.  
Yellow hues of Beryl is known as Heliodor
MINERAL: beryl
COLOR: Yellow
REFRACTIVE INDEX: 1.577 to 1.583
BIREFRINGENCE: 0.005 to 0.009
MOHS HARDNESS: 7.5 to 8.0
-Source AGTA