Takéuchiite, a new oxyborate mineral from Långban, Sweden

Jan-Olov Bovin; M. O'Keeffe

Article navigation

Other| December 01, 1980

Takéuchiite, a new oxyborate mineral from Långban, Sweden

Jan-Olov Bovin;

Jan-Olov Bovin

Ariz. State Univ., Chem. Dep., Tempe, AZ, United States

Search for other works by this author on:

GSW

Google Scholar

M. O'Keeffe

Search for other works by this author on:

GSW

Google Scholar

Author and Article Information

Jan-Olov Bovin

Ariz. State Univ., Chem. Dep., Tempe, AZ, United States

M. O'Keeffe

Publisher: Mineralogical Society of America

First Online: 03 Mar 2017

Online ISSN: 1945-3027

Print ISSN: 0003-004X

American Mineralogist (1980) 65 (11-12): 1130–1133.

Abstract

Takéuchiite, ${Mg}_{1.59} {Mn}_{0.42}^{2 +} {Mn}_{0.78}^{3 +} {Fe}_{0.19}^{3 +} {Ti}_{0.01}^{4 +} {BO}_{5}$ ⁠, occurs as acicular crystals in granular dolomite and calcite from the Långban mine, Värmland, Sweden. It is orthorhombic, space group Pnnm or Pnn2 with a = 27.50(1), b = 12.614(2), c = 6.046(1)Å, V = 2097Å³, Z = 24. The strongest lines in the X-ray diffraction pattern (d, in Å; intensity; hkl) are: 1.511, 100, 004; 2.60, 90, 640; 5.20, 85, 320; 2.035, 80, 850 (and 922, 10 02) and 3.02, 65, 002. Takéuchiite is black and opaque with metallic luster and brown streak and has a hardness of 6. The calculated density is 3.93 g/cm³. Morphologically, takéuchiite forms long prismatic crystals with dominant form {320}.