Wood material is often preserved in the rock record. Most commonly it is preserved as petrified wood, which is wood replaced with small grains of quartz. This is truly a replacement, unlike fossilized bones where the original bone is usually still present and minerals grow around it. In Indonesia, volcanic activity is common and volcanic fluids that flow through the layers of ash and lava are rich in silica. When trees are buried within the ash, the silica can replace the wood, depositing opal.
The shield collection is a new designer cabochon collection by Janet Bertog of Heather Canyon.