Heliodor

Heliodor is the name given to a greenish yellow variant of the mineral Beryl, while golden yellow Beryl is referred to as ‘Golden Beryl’. However, the names are often used interchangeably for both variants.

Beryl has a hardness of 7.5-8 on the Mohs scale and occurs in several other gemstone variants – Emerald, Aquamarine, Morganite, and Goshenite.

High grade Heliodor is faceted and sold for jewellery making.

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Appearance, Uses and History

Heliodor is the name given to a greenish yellow variant of the mineral Beryl, while golden yellow Beryl is referred to as ‘Golden Beryl’. However, the names are often used interchangeably for both variants.

Beryl is primarily used for jewellery making or sold as mineral specimens – and Heliodor is no exception.

Beryl was used for eyeglasses in 13th century Italy as the processes for glassmaking could not produce lenses with enough clarity.

The worlds largest known crystal is Beryl, an 18 metre tall crystal from Madagascar weighing around 380 tons.


Locales

Heliodor crystals are found in Afghanistan, Brazil, Czechia, France, Madagascar, Norway, Pakistan, Portugal, Russia, Ukraine, the USA, Vietnam, and Zimbabwe.

I’ve held stock from Afghanistan, Brazil, Pakistan, Russia, and Vietnam, some of which was very nice – the Afghani material and the Vietnamese material tend to have an excellent colour while keeping towards the budget end of the pricing spectrum.


Mineralogy

Chemistry
A cyclosilicate mineral with the formula Be3Al2Si6O18. Variations in this formula are likely to be caused by the minerals that cause the colours.
Colours and Variations
Yellow, green-yellow, golden yellow.
Streak
N/A
Luster
Vitreous
Fracture
Conchoidal to uneven.
Transparency
Translucent to transparent
Crystal habit
Prismatic hexagons with flat terminations, not striated.
Mohs hardness
7.5 – 8
Specific Gravity
2.6 – 2.8
Fluorescence
N/A
Easiest testing method
Examination of the crystal structure, colour.
Common Treatments
Commonly heat treated, dyed, or irradiated.

Photos of Heliodor


Reasonable quality crystal from Vietnam

Extremely fragmented crystals from Brazil.

Hazards and Warnings

Almost all rocks, minerals (and, frankly, almost all other substances on earth) can produce toxic dust when cutting, which can cause serious respiratory conditions including silicosis.

However, Beryl is a beryllium compound which can cause Berylliosis.

Given that this disease can be caused by as little as a single exposure to Beryllium, any lapidary intending to work Beryl should do careful research and make sure their extraction and respirators are correctly rated.

When cutting or polishing rocks, minerals, shells, etc, all work should be done wet to minimise the dust, and a suitable respirator or extraction system should be used.


Translations

Arabic:

  • هيليودور

Hindi:

  • हेलिओडोर

Portuguese:

Bengali:

  • হেলিওডর

Indonesian:

Punjabi:

English:

  • heliodor
  • beryl

Italian:

Russian:

  • гелиодор

French:

  • héliodore

Japanese:

  • ヘリオドール

Spanish:

German:

Korean:

  • 헬리오도르

Thai:

  • เฮลิโอดอร์

Gujurati:

Mandarin and Traditional Chinese:

  • 金色绿宝石
  • 黄透绿柱石
  • 黄绿宝石

Urdu:

  • ہیلیوڈور

Further Reading / External Links

  • https://www.mindat.org/min-6727.html
  • https://www.gemsociety.org/article/heliodor-golden-beryl-jewelry-gemstone-information/
  • https://geology.com/gemstones/heliodor/