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Heliodor (Golden Beryl)
Current inventory:  2 gems
 

Chemistry:  Be₃Al₂Si₆O₁₈ + Fe  [Beryllium Aluminum Silicate]

Discovery: 1912;   IMA status: Heliodor - Not Valid; Beryl - Valid
The name Heliodor was orinally applied as a trade name to "Golden Beryl" from Rossing, Namibia. Heliodor is from the Greek helios (sun) due to its yellow color. The name Beryl is from ancient Greek meaning "precious blue-green color of sea water" stone which was originally applied only to Aquamarine but was later used for the Beryl family.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/E.12-10

Nickel-Strunz 10th Ed. ID:

9.CJ.05

9 : SILICATES (Germanates)
C : Cyclosilicates
J : [Si₆O₁₈]₁₂- 6-membered single rings (sechser-Einfachringe), without insular complex anions

Related to:

Beryl Group: Beryl, Bazzite, Indialite, Stoppaniite, Pezzottaite. Beryl Series

Crystal Data

Crystallography:

Hexagonal - Dihexagonal Dipyramidal

Crystal Habit:

Crystals are prismatic to tabular; may be complexly terminated by pyramids, to 18 m and 180 t. Also radial, trapiche, columnar; granular to compact.

Twinning:

Rarely

Physical Properties

Cleavage:

[0001] Imperfect

Fracture:

Conchoidal to Uneven

Tenacity:

Brittle

Hardness (Mohs):

7.5 - 8.0

Hardness (Vickers):

VHN200=1239 - 1467 kg/mm²

Density:

2.63 - 2.92 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Pale Yellow, Yellow, Golden Yellow

Transparency:

Transparent to Translucent

Luster:

Vitreous (glassy)

Refractive Index:

1.567 - 1.572  Uniaxial ( - )

Birefringence:

0.005- 0.007

Dispersion:

0.014 (low)

Pleochroism:

n/a

Occurances

Geological Setting:

In granites and granite pegmatites, rarely in nepheline syenites. Also in maffic metamorphic rocks, low- to high-temperature hydrothermal veins and in vugs in rhyolite.

Co-Type Localities:

Rössing Mine, Arandis, Arandis District, Erongo Region, Namibia
Litchfield Co., Connecticut, USA

Year Discovered:

about 1912

View mineral photos:

Heliodor Mineral Photos and Locations

More Information

Mindat.org (Heliodor)
Mindat.org (Beryl)
Webmineral.com (Beryl)

Heliodor (or Golden Beryl) is the yellow color variety of the Beryl family of minerals that includes Aquamarine (blue), Bixbite (red), Emerald (green), Goshenite (colorless), Heliodor (yellow), Morganite (pink) and recently, Pezzottaite (pink and red). Heliodor gets its yellow color from traces of ferric iron added to the basic Beryl formula. Large, clean crystals are available from a few locations. Minas Gerais, Brazil is one of the sources of Golden Beryl crystals.
 

  
Heliodor (Golden Beryl) gems for sale: