As long as the channel(s) is not clogged or solutions keep coming in, the growing process would continue on. Note thin & pink agate band in this large specimen in the picture above which tend to be called "Floating Band". The quartz crystals in this specimen did not clog the channel, so new layers (agate, then quartz, then agate) would keep growing until it's full. This kind of specimen is one of several things that support (not necessarily prove) an idea of "open system: where the agate and quartz form in successive layers in respect to wet & dry periods.