This petrified wood is from the Miocene age and about 15.5 million years old.
Only this location in Washington produces this semi precious gemstone material Petrified Sycamore Wood that, when designer cabochons are cut right, the cabochons will have this unique "feather" pattern.
Tree trunks were buried under several hundred yards of sediment. Over the course of time the wood was replaced by cryptocrystalline quartz, largely chalcedony (jasper). During the replacement process by silica carried in underground waters, even the most minute details of the woody structure was preserved.
Petrified Wood in general is a stone of patience, and slow and steady growth. Petrified Wood can help one overcome limiting emotional patterns handed down through one's ancestors.