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Geosciences LibreTexts

16.4.7: Heliodor

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Heliodor
Chemical composition Be3Al2(SiO3)6Beryllium aluminum silicate
Crystal system Hexagonal
Habit Prismatic
Cleavage Poor, basal
Fracture Conchoidal to uneven
Hardness 7.5
Optic nature Uniaxial -
Refractive index 1.57 - 1.58
Birefringence 0.004 - 0.009
Dispersion Low, 0.014
Specific gravity 2.7 - 2.9
Lustre Vitreous
Pleochroism Weak to moderate (shades of body color)

Heliodor is the golden yellow or golden green variety of the mineral beryl. It is a beryllium aluminum silicate. The golden color is produced when iron replaces some of the aluminum in the crystal structure. Heliodor can contain trace amounts of uranium, making it slightly radioactive. Heliodor was discovered in Namibia in 1910 in a pegmatite that also produced aquamarine, which is also colored by iron.
Crystals form very distinct hexagonal prisms that are some of the largest crystal examples in gemology. The largest faceted heliodor, 2,054 carats, is on display at the Smithsonian Institution in Washington D.C.
The name heliodor is Greek, meaning "gift from the sun". This stone is not often used in jewelry because it lacks brilliance and fire. Heliodor is found in Minas Gerais and Goias in Brazil, in Ukraine in Russia, and also in Connecticut and Maine in USA.
Heliodor is considered a talisman for those named Hugh.


This page titled 16.4.7: Heliodor is shared under a CC BY-NC-SA 2.5 license and was authored, remixed, and/or curated by gemology via source content that was edited to the style and standards of the LibreTexts platform.

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