Chrysoberyl
Current inventory:  0 gems
 

  
The name Chrysoberyl is from the Greek word chrysos meaning golden, in allusion to the minerals color, and beryl.

Discovered in 1789; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

BeAl₂O₄

Beryllium Aluminum Oxide

Molecular Weight:

126.97 gm

Composition:

Berylium

7.10 %

Be

19.70 %

BeO

Aluminum

42.50 %

Al

80.30 %

Al₂O₃

Oxygen

50.40 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/B.07-10

Nickel-Strunz 10th Ed. ID:

4.BA.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
B : Metal: Oxygen = 3:4 and similar
A : With small and medium-sized cations

Related to:

The Cr-analogue of Mariinskite.

Varieties:

Alexandrite, Ceylonese Chrysolite, Chrysolite Cat's Eye, Cymophane

Synonyms:

Aluminate of Glucina, Alumoberyl, Chrysberil, Chrysoberil, Chrysopal (of Delamétherie), Crisoberilo, Krisoberil, Krysoberril, Oriental Chrysolite

Crystal Data

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

Crystals are tabular on {001} or short prismatic along [100], to 22 cm; prominently striated on {001} || [100].

Twinning:

Common on {130}, producing either flattened heart-shaped or pseudohexagonal multiple contact and penetration twins.

Physical Properties

Cleavage:

Distinct on {110}, imperfect on {010}, poor on {001}.

Fracture:

Irregular/Uneven to Conchoidal

Tenacity:

Brittle

Moh's Hardness:

8.5

Density:

3.75 (g/cm³)

Luminescence:

Weak red in SW and LW UV

Radioactivity:

Not Radioactive

Optical Properties

Color:

Various shades of green, yellow, brownish to greenish black, may be raspberry-red under incandescent light when chromian; colorless, pale shades of yellow, green, or red in transmitted light.

Transparency:

Transparent to translucent, may be opaque and chatoyant with oriented inclusions.

Luster:

Vitreous

Refractive Index:

1.746 - 1.756  Biaxial ( + ) 

Birefringence:

0.010

Dispersion:

r > v

Pleochroism:

X = red; Y = yellow-orange; Z = emerald-green. Exhibits a bluish opalescence or chatoyancy, notably on {010}. Also asteriated with a cat's eye effect.

Occurances

Geological Setting:

Characteristic of some granite pegmatites associated with high-grade mica schists or reaction zones in ultramafic rocks; also detrital in placers.

Common Associations:

Quartz, Muscovite, Albite, Beryl, Columbite, Tourmaline, Topaz, Kyanite, Staurolite (granite pegmatites); Phenakite, Apatite, Tourmaline, Fluorite (reaction zone pegmatites).

Common Impurities:

Fe, Cr, Ti

Type Locality:

Takowaja, Russia

Year Discovered:

1789

View mineral photos:

Chrysoberyl Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Chrysoberyl is a beautiful gem and well suited for jewelry use. The combination of high hardness (8.5) and indistinct cleavage make it very durable. Although its dispersion is low, it is a very bright and colorful gem. Cat's eye Chrysoberyl is also available. Other gems such as diopside and apatite may be called cat's eyes, but Chrysoberyl was the original cat's eye gem. It is the finest cat's eye of gems. The silky fibers are so fine that a microscope is needed to see the individual fibers. This creates a very sharp cat's eye effect.

Chrysoberyl is not very well known in the gem world. It is somewhat overshadowed by one of its more famous varieties, Alexandrite. Alexandrite is the best known and most valuable variety of Chrysoberyl. The quality of Alexandrite's color change effect is what accounts for its desirability and value. It can change from shades of green or blue-green in daylight to shades of mauve, violet, purple or even red in incandescent light. Alexandrite is also available as a cat's eye gem.

Occurances of Chrysoberyl are widespread, however fine crystals are uncommon. Notable localities include: from many places in Brazil, with exceptional crystals from Tancredo, Itagua¸cu, and Colatina, Espirito Santo; from Faria Lemos, Santa Luzia de Carangola, and Americana, Teófilo Otoni, Minas Gerais; at Campo Formoso, Teixeira de Freitas, and Cachoeira, Bahia. From Maršíkov, Šumperk, Moravia, Czech Republic. At the Izumrudnye mines, Tokovaya River, near Yekaterinburg (Sverdlovsk), and Mursinka, Ural Mountains, Russia. From Miakanjovato, near Lake Alaotra, northeast of Ambatosoratra, Madagascar. Near Masvingo (Ft. Victoria), Zimbabwe. Abundant in gem gravel placers in the Ratnapura district, Sri Lanka. In the USA, from near Golden, Jefferson County, Colorado; in Maine, at Topsham, Sagadahoc County, from Paris, Norway, and Hartford, Oxford County, and elsewhere.
 

  
Chrysoberyl gems for sale:

We have not photographed our Chrysoberyl gems yet. Please check back soon!