  A silica colloidal crystal obtained by centrifugation at 9 G for 2 days in
water was annealed by additional stronger centrifugation at 50 G for 5 days.
The number of the striations observed in the colloidal crystal under crossed
polarized light decreased at some parts in a growth container after additional
centrifugation, while the number alse increase at the other parts. The decrease
probably shows the shrinkage of the stacking disorders under high gravity,
while the increase probably shows the production of new stacking disorder.
