[3][2] The formula given is derived from the original one and shows a separate silicon at the M4 site, basing on the nomenclature of the eudialyte group.
At the type locality taseqite occurs in albitite veins, together with aegirine, analcime, catapleiite, ferrobustamite, hemimorphite, pectolite (silicates); ancylite-(La), calcite, dolomite, strontianite (carbonates); fluorapatite, and sphalerite.
[5] Admixtures in taseqite include potassium and manganese, with traces of yttrium, cerium, hafnium, tantalum, and tin.
The absorption peak at 740 cm−1 is typical of many minerals, including oneillite and eudialyte; it is shifted in the spectra of golyshevite (747 cm−1) and georgbarsanovite (751 cm−1).
The similar band in the IR spectra of EGMs is due to the bending vibrations of silicon‒oxygen rings, in which electric dipole moment oscillates mainly along the c axis [1].
The region of O–H stretching vibrations contains a weak peak of complex shape at 3632 cm−1, with shoulders at 3660 and 3670 cm−1, and a wide band in the range of 3400–3550 cm−1, which is due to the water molecules forming relatively strong hydrogen bonds.