Jeremejevite
Current inventory:  2 gems
 

  
Named after P.V. Jeremejev (1830 - 1899), a Russian mineralogist and engineer.

Discovered in 1883;   IMA status:  Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Al₆B₅O₁₅(F,OH)₃

Aluminum Borate Fluoride Hydroxide

Molecular Weight:

511.93 gm

Composition:

Aluminum

31.62 %

Al

59.75 %

Al₂O₃

Boron

10.56 %

B

34.00 %

B₂O₃

Hydrogen

0.10 %

H

0.88 %

H₂O

Oxygen

48.44 %

O

Fluorine

9.28 %

F

9.28 %

F

  - %

F

-3.91 %

 — O=F₂

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Borates

Strunz 8th Ed. ID:

5/G.05-30

Nickel-Strunz 10th Ed. ID:

6.AB.15

6 : BORATES
A : Monoborates
B : BO₃, with additional anions; 1(D) + OH, etc.

Related to:

None

Members of Group:

None

Varieties:

None

Synonyms:

Eremeevite, Eremeyevite, Jeremeievite, Jéréméiéwite, Jeremejeffite, Jeremejewite, Yeremeyevite

Crystal Data

Crystallography:

Hexagonal - Dipyramidal

Crystal Habit:

Crystals are typically hexagonal prismatic, may be tapered by vincinal forms, with pyramidal termination, to 10 cm.

Twinning:

None

Physical Properties

Cleavage:

None observed

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

6.5 - 7.5

Density:

3.28 - 3.31 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Piezoelectric

Optical Properties

Color:

Colorless, pale to dark cornflower Blue, pale Yellowish Brown; Colorless to pale Blue in transmitted light, typically sector zoned.

Transparency:

Transparent

Luster:

Vitreous

Refractive Index:

1.640 - 1.653  Uniaxial ( - ); may be anomalously Biaxial ( – ) in sector-zoned crystals

Birefringence:

0.0130

Dispersion:

Distinct; r > v

Pleochroism:

Light blue/colorless to light yellow

Occurances

Geological Setting:

A rare late hydrothermal mineral formed in granitic pegmatites.

Common Associations:

Albite, Tourmaline, Quartz, Gypsum (Cape Cross, Namibia)

Common Impurities:

None

Type Locality:

Soktuj Gora, Adun-Cholon Range, Nertschinsk (Nerchinsk) Mines, Buriatia (Buryatia) Republic, Transbaikalia (Zabaykalye), Eastern-Siberian Region, Russia

Year Discovered:

1883

View mineral photos:

Jeremejevite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Jeremejevite was originally discovered on Mt. Soktui in Russia as minute crystals not large enough for faceting. More recent finds at "Mile 72" near Khan River, north of Swakopmund, Namibia and the Eifel district in Germany have yielded beautiful pale blue crystals. The crystals are elongated and very small. Therefore, gems are small and usually faceted in an elongated emerald or baguette cut. Faceted Jeremejevite is extremely rare because most sources have produced little material or are mined out. Jeremejevite is also piezoelectric.

Jeremejevite is found at only a few localities. From Mt. Soktui, Nerschinsk district, Adun-Chilon Mountains, Siberia, Russia. In the Kukurt massif, Pamir Mountains, Tajikistan. Relatively large crystals have been found at a prospect near Cape Cross, at Mile 72, about 100 km north of Swakopmund, and from Ameib, Erongo Mountains, Namibia. At Wannerköpfe and Emmelberg, near Üdersdorf, Eifel district, Germany.
 

  
Jeremejevite gems for sale: