Dr. Nagy I. Zoltán szerk.: Fragmenta Mineralogica Et Palaentologica 4. 1973. (Budapest, 1973)

The bisectrix of the (010) face pole of the two complexes: f M = + 0.55505 i - 0.73427 £ + 0.39086 k o The mean value of the unit vector resulting in from the measu­rements of the optical directions and crystallographic ones: f = + 0.55406 i - 0.73322 i_ + 0.39418 k — o — — In the following the twinning axis is transformed into the sys­tem of co-ordinates in which X' = Kj Y* = Mj Z» = Zj fl M + 0.49798 ±* + 0.84825 £» + 0.03938 k' The Goldschmidt values of this: <p = 31.9°, P = 87.75°, i.e. this is a normal twinning law according to (130). The theore­tical values: 0 , = 30.20°, P= 90.0°. The optical symmetry axes being transformed into the system of co-ordinates of the first complex: - 0.46711 i' + 0.84910 k» - 0.48181 i» + 0.00625 k' + 0.73569 j.' + 0.54483 k' Eight twin crystal This crystal occurs in the same rock where the fifth twin crys­tal was found. The measurement data and vector components of the plagioclase shown in Pig. 9. are the following: I. = the (010) cleavage and composition plane in the complex containing the members A, B and C. tLj = 119° hj = 19.5° a' = - 0.24375 i» ~ B o b» = + 0.88485 i' cl = + 0.39444 i'

Next

/
Thumbnails
Contents