亚利桑那州中东部的石化森林国家公园有两个地质构造：晚三叠世Chinle组和Mio-Pliocene Bidahochi组。整个公园内发现的石化原木是名为Araucarioxylon arizonicum的针叶树，这是一种晚三叠世化石松树，生长在2.25亿年前。色彩斑斓的彩绘沙漠荒地属于同一时期，由膨润土组成，膨润土是火山灰改变的产物。公园里的梅萨斯和公园是侵蚀造成的其他特征。大约20万年前，一场古老的洪水将针叶树的原木带入了古老的河流系统以及大量的沉积物和碎片。原木埋藏得如此之深，以至于氧气被切断，腐烂减缓了数百年的过程。从火山灰中溶解的铁，碳，锰和二氧化硅等矿物质被吸收到木材的细胞结构中，随着它慢慢分解而取代有机物质。结果是石化木材由几乎坚固的石英透明石英，紫色紫水晶，黄色黄水晶和烟熏石英组成。每件作品都像一个巨大的彩虹色水晶，经常在阳光下闪闪发光，仿佛被闪光所覆盖。
加拿大麦吉尔大学论文代写：彩虹色水晶
The Petrified Forest National Park in the eastern and central Arizona has two geological formations: the Late Triassic Chinle Formation and the Mio-Pliocene Bidahochi Formation. The petrified log found throughout the park is a conifer called Araucarioxylon arizonicum, a late Triassic fossil pine that grew 225 million years ago. The colorful painted desert wasteland belongs to the same period and consists of bentonite, which is a product of volcanic ash change. Mesas and the park in the park are other features of erosion. About 200,000 years ago, an ancient flood brought the logs of conifers into the ancient river system and a lot of sediments and debris. The logs were buried so deeply that the oxygen was cut and the decay slowed down the process for hundreds of years. Minerals such as iron, carbon, manganese and silica dissolved from volcanic ash are absorbed into the cellular structure of the wood, and as it slowly decomposes, it replaces organic matter. The result is that the petrochemical wood consists of almost solid quartz transparent quartz, purple amethyst, yellow citrine and smoked quartz. Each piece is like a huge iridescent crystal, often shining in the sun, as if covered by flash.