Taikanite

taikanite

braunite

namansilite

strakhovite

Images

Formula: BaSr2Mn3+2O2(Si4O12)
Inosilicate (chain silicate), barium-, strontium- and manganese- bearing mineral
Crystal System: Monoclinic
Specific gravity: 4.72 measured, 4.81 calculated
Hardness: 6 to 7
Colour: Emerald-green, blackish green
Common impurities: Al,Pb,Mg,Ca,Na,K
Environments

Hydrothermal environments

Localities

There are two co-type localities, the Dzhavodi area and the Zaoblachnyi area, both in the Ir-Nimi manganese deposit, Taikan Ridge, Khabarovsk Krai, Russia.
At the type localities taikanite occurs as equant grains several tenths of a mm in size, rarely elongate to 1.6 mm, in hydrothermal manganese ores related to alkalic dikes intruding Cambrian (538.8 to 485.4 million years ago) limestones and siliceous rocks. Associated minerals include braunite, namansilite and strakhovite (HOM, AM 72.226).

At the Wessels Mine, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa, the sample containing taikanite came from a sugilite-cemented breccia of hausmannite and braunite. These sugilite breccias occur in the middle of the ore body. Pink veinlets of serandite-pectolite, sugilite, potassic-mangani-leakeite, and hennomartinite formed along the contacts of the breccia fragments. The compositions and optical properties of the serandite-pectolite crystals vary within the veinlets, and the crystals change from pink to colourless. In addition, thin sections of the veinlets show occasional dark red to orange-yellow crystals that are probably the disilicate kentrolite.
The sugilite breccia contains sugilite and strongly pleochroic aegirine with a blue-green tint. The pink veinlets are zoned, showing a rim of aegirine and the amphibole containing K, Na, Li and Mn3+. The centres of the veinlets are dominated by a zone of comblike serandite-pectolite. Within this zone, fibres of potassic-mangani-leakeite and ideomorphic sugilite have grown obliquely to the veinlets.
Aggregates of taikanite occur in this serandite-pectolite felt. Taikanite is strongly pleochroic (blue-green, turquoise, dark marine blue) and has a preferred orientation oblique to the vein walls. Most taikanite is prismatic but some samples form fine intergrowths with serandite-pectolite (AM 78.1.1088-1095).

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