Featured in this lot is a Holbrook, Arizona Polished Triassic Period Chinle Formation Petrified Wood Slab. A slab of fossilized wood, the petrified tree trunk is sliced crossways and polished to a mirror finish on one of the planar faces to showcase the broad interior rings of the tree as well as the incredible colouration. The petrified wood slab is a wonderfully preserved specimen from the area that abuts Petrified Forest National Park, one of the largest and most colourful concentrations of petrified wood in the world. The petrified wood in and around Petrified Forest National Park is part of the Chinle Formation – layers of sediment over 900 feet thick that formed between 200 and 250 million years ago. Researchers have dated the fossilized trees in this area to around 211 to 218 million years old, around the time of the Late Triassic. Although the fossilized trees are nearly solid quartz – typically a colourless, translucent crystal – impurities in the mineral can create beautiful colours. Inclusions of iron create deep reds and oranges; cobalt and chromium lead to blues and greens; manganese can result in vibrant orange and purple hues; and carbon can create a jet black colour. Because of its colourful hues, the petrified wood in northeastern Arizona is known as ‘rainbow wood’ and is some of the most vivid in the world. The specimen has one face polished, is solid and rock-like with minimal fracturing. Interior patterns are strong and varied with concentric rings radiating outwards. Colour is mostly reddish rust earth tones with streaks of grey and black. The condition of this petrified wood slab is well preserved with no artificial breaks or wear marks and shows a well preserved overall condition. Slab measures 7.25" x 7.75" x 1"D and its weight is 3lb 4oz.*