Fig. 30.-Chessboard albitization of K-feldspar
A---Co-orientation albitization (chessboard
albite)[K(Ab)] takes place at the border of K-feldspar (with grid twinning)
phenocryst. There is sharp contact between the chessboard albite [K(Ab)] and
the unalbitized K-feldspar (K).
B---Chessboard albite keeps the same orientation as
the primary K-feldspar with (001) cleavage. The compositional plane of the
chessboard albite is zigzag and variable.
C---Chessboard albite patches are distinct from the
albite lamellae in K-feldspar.
Samples are
selected from sodic metasomatite of Jiling granite,