Fossil Araucaria tree, American petrified wood from Arizona. The petrified trees of the Arizona desert are those with the widest range of colours. The latter were brought by the richness of the minerals present in the soils during their change of state from wood to stone. But it is also those which have been the most tormented, traveling in the rivers, colliding with each other and then crushed by heavy masses of sediment. The hardness is such that the shafts are often so cracked that the polishing of these plates is very long and requires a lot of patience and expertise. This Mesozoic piece is a cut from a 220 million year old fossil Araucaria. Back reinforced with fiberglass.
The alterations suffered when the tree was a wood cause deformations with curved shapes, in rounded segments. They are generated by a higher pressure than the wood texture can support. It is a tree with altered tissues, made porous by a history of a few years spent lying on the ground of a forest, with a very high rate of hygrometry favourable to decomposition. It probably died like trees, old age or a gust of wind, but not a flooded river surge like some swamped forests. Luckily, still healthy peripheral areas acted as shields and nevertheless allowed an altered tree to resist pressure. These strongest protections, which protected it 220 million years ago, are the most translucent today and nowadays, the most altered zones are made of softer stone, the hardest zones, those that were spared from decay. These differences in hardness make polishing this heterogeneous surface more delicate. Many trees that were too badly altered did not survive, were too flattened, too perforated to remain a support for petrifaction. For this fossil wood, an area, however, escapes this logic, the perforations due to decomposition have been crystallized, the micro cavities filled with tiny dotted dots of colored quartz, accompanied by this shade of subtle ochres, coming from iron, at different temperatures (nuances that explain themselves in the same way as the colored nuances of the bricks in a wall). The tree was lying on its most rectilinear base. He must have encountered obstacles that had a negative effect on its periphery, this moving black-and-white drawing, so elegant. And even live shocks of stone against stone, hence these stone breaks welded by quartz crystallization, which must have taken a few million years to reattach the pieces.
Really good condition