Kurgantaite

Korshunovskoye (Korzunovskoe; Korzhunovska; Korshunovskiy) Iron mine, Zheleznogorsk, Irkutskaya Oblast', Prebaikalia (Pribaikal'e), Eastern-Siberian Region, Russia
© Knut Eldjarn

Formula:

CaSr[B

]Cl · H

System:

Triclinic

Colour:

Colourless to white

Hardness:

6 - 6½

Name:

named for the type locality, Kargan-tau, Kazakhstan

1952 described as a new mineral, 1982 discredited as a strontian variety of Tyretskite, 2000 revalidated and IMA approved.

Classification of Kurgantaite

IMA status:

Approved 2002

Explanation of status:

IMA Code 00-B - Kurgantaite revalidated (2002)

Strunz 8th edition ID:

5/0.0-

Nickel-Strunz 10th (pending) edition ID:

6.ED.05

6 : BORATES
E : Pentaborates
D : Tekto-pentaborates

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Type Occurrence of Kurgantaite

Type Locality:

Kurgan-tau, Inder B deposit and salt dome, Atyrau (Gur'yev), Atyrau Oblysy (Atyrau Oblast'), Kazakhstan

General Appearance of Type Material:

Fine-grained nodules up to 4 cm across.

Year of Discovery:

1952

Geological Setting of type material:

in a borate deposit

Physical Properties of Kurgantaite

Lustre:

Vitreous

Diaphaneity (Transparency):

Transparent

Colour:

Colourless to white

Streak:

white

Hardness (Mohs):

6 - 6½

Hardness Data:

Measured

Tenacity:

Brittle

Cleavage:

Imperfect/Fair

Fracture:

Irregular/Uneven

Density (measured):

2.99 g/cm³

Density (calculated):

3.04 g/cm³

Crystallography of Kurgantaite

Crystal System:

Triclinic

Class (H-M):

1 - Pedial

Space Group:

Cell Parameters:

a = 6.573Å, b = 6.445Å, c = 6.369Å
α = 60.995°, β = 61.257°, γ = 77.191°

Ratio:

a:b:c = 1.02 : 1 : 0.988

Unit Cell Volume:

V 206.9 Å³

Optical Data of Kurgantaite

Type:

Biaxial (+)

RI values:

n_α = 1.637 n_β = 1.638 n_γ = 1.675

2V:

Calculated: 19°

Maximum Birefringence:

δ = 0.038

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.

Surface Relief:

Moderate

Pleochroism:

Non-pleochroic

Chemical Properties of Kurgantaite

Formula:

CaSr[B

]Cl · H

All elements listed in formula:

B, Ca, Cl, H, O, Sr

Relationship of Kurgantaite to other Species

6.ED.05

Hilgardite

Cl·H

6.ED.05

Tyretskite

OH·H

Other Names for Kurgantaite

Synonyms:

IMA2000-B

Other Languages:

German:	Kurgantait
Spanish:	Kurgantaita

Other Information

Health Warning:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Kurgantaite

Reference List:

Yarzhemsky, Ya.Ya. (1952): Kurgantaite – a new borate mineral.- Mineral. Sbornik, Lvov Geol. Obshchest. 6, 169-174 (in Russian).

Pekov, I.V., E.V. Lovskaya, N.V. Chukanov, A.E. Zadov, V.N. Appolonov, D.Yu. Pushcharovsky, O. Ferro & S.A. Vinogradova (2001): Kurgantaite CaSr(B3O9)Cl · H2O: revalidation of the mineral species and new data.- Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva: 130(3), 71-79 (in Russian).

Grew, E.S., and Anovitz, L.M. (1996) BORON: Mineralogy, Petrology and Geochemistry, second edition, as revised (2002).