This specimen began as a large spodumene crystal (or crystal group) which overgrown and replaced by silky brown, fine-grained cookeite. Eventually all of the spodumene had been dissolved and/or transformed, leaving the layered and somewhat cavernous sample you see here. Small spots of residual spodumene remain. Aesthetic and large for the locality. A few minor incomplete spots, negligible in this case. A choice example.