Heliodor is a member of the beryl family. This stone is known for its range of yellow colors — from pale yellow, greenish yellow, orange-yellow, to a deep golden orange. Heliodor can be faceted for jewelry use.

Heliodor is also known as golden beryl. However, some gemological references distinguish between the terms heliodor and golden beryl, using “heliodor” strictly for beryls with a greenish yellow color and “golden beryl” for beryls with pure yellow to gold color. Other references, notably Walter Schumann, reject heliodor as a distinct variety of beryl altogether and consider heliodors as simply “weak-colored” golden beryls.

Greenish yellow heliodors may be heated and turned into aquamarines. This is known to have happened with Ukrainian material. Better known by consumers, faceted aquamarines will generally sell for more than heliodors. However, aquamarines may also be irradiated and turned into heliodors. Reportedly, pale aquamarines from Vietnam may receive radiation treatments in Laos, only to be returned to Vietnam and sold as natural heliodors.