Tamaite, the Ca-analogue of ganophyllite, from the Shiromaru mine, Okutama, Tokyo, Japan.

Accession number;00A0952450
Title;Tamaite, the Ca-analogue of ganophyllite, from the Shiromaru mine, Okutama, Tokyo, Japan.
Author;MATSUBARA S(National Sci. Museum, Tokyo, Jpn)   MIYAWAKI R(National Sci. Museum, Tokyo, Jpn)   TIBA T(National Sci. Museum, Tokyo, Jpn)   IMAI H(Yamanashi Jewellery Art School, Yamanashi, Jpn)   
Journal Title;J Mineral Petrol Sci
Journal Code:G0150B
ISSN:1345-6296
VOL.95;NO.5;PAGE.79-83(2000)
Figure&Table&Reference;FIG.2, TBL.3, REF.14
Pub. Country;Japan
Language;English
Abstract;Tamaite, (Ca, K, Ba, Na)3-4Mn24(Si, Al)40(O, OH)112 21H2O, the Ca-analogue of ganophyllite, is found from the Shiromaru mine, Okutama, Tokyo, Japan. It is monoclinic, P21/a, a=16.64(1), b=27.11(2), c=25.35(2).ANGS., .BETA.=98.74(7).DEG., Z=4. The strongest lines in the X-ray powder diffraction pattern are 12.6 (vvs) (002), 3.46 (m) (027), 3.13 (s) (008), 2.84 (s) (38 -2), 2.69 (vs) (38 -4), 2.60 (s) (602), 2.46 (s) (60 -6), 2.38 (m) (604), 1.623 (m) (98 -2), 1.609 (m) (3 10 11). Electron microprobe and Karl-Fischer analyses gave SiO2 41.23, Al2O3 7.79, FeO 0.16, MnO 35.17, MgO 0.23, CaO 1.94, BaO 2.03, Na2O 0.34, K2O 0.82, H2O 11.07, total 100.78wi%, and lead to the empirical formula, (Ca1.65K0.83Ba0.63Na0.53).SIGMA.3.64Mn23.71Mg0.27Fe0.11Al0.12).SIGMA.24.21(Si32.81Al7.19).SIGMA.40.00 O95.27(OH)16.73 21H2O on the basis of O=133. It is transparent and colorless to pale yellowish brown in color with vitreous to pearly luster. The streak is white and cleavage perfect on {001}. The Mohs' hardness is about 4. The measured and calculated densities are 2.85(5)g/cm'3' and 2.83g/cm'3', respectively. It is colorless in thin section and optically biaxial negative with .BETA.=1.612(2) and 2V<15.DEG.. It occurs as veinlets up to 1.5mm thick composed of micaceous platy crystals under 0.5mm in diameter and as spotted crystals in celsian-barian orthoclase veinlets cutting host rocks of metamorphosed manganese ore deposit. The mineral is considered to be formed during later stage activity of low grade metamorphism. (author abst.)