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The Origins of Northern Arizona Petrified Wood

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  --- In progress ---   The dominant source of Petrified Wood in Northern Arizona and Southern Utah is the Chinle Formation. The Chinle consists of mudstones with occasional siltstone, sandstone, and other accessory units. Below is a brief summary of the petrified woods geologic origins    Geologists believe this wood was deposited along the banks of a river system while dinosaurs roamed the earth in the Mesozoic era. The river system flower overland a long distance and had mamy systems of ponds, wetlands, and tributaries.    Many of the wood samples found are Ginko trees, which were much more common in that era. When large floods logjammed the river wood blanketed the river floodplains and was sealed in a blanket of sediment before it could decompose. That process results in wood being preserved as stone because mineralization happens slowly and directly replaces the woods cellular structure with mineral. Floodplains are dominanted by fine clay rich sedime...
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How to Identify Copper Ore

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---In progress--- How do you identify copper ore in the field? This is not meant to be a fully comprehensive guide just some quick simple tips when in the field.   Typically copper ores form in hydrothermal systems where hot water is circulated through fractures in rock depositing valuable minerals. A prime place to hunt is fractures in specific rocks to spot minerals and the larger fracture and fault zones that form in rock units as a general area. If you are lucky you may come upon a massive volcanogenic deposit but those are typically located inside mining jurisdictions.  Minerals commonly associated with copper include pyrite, Galena, sphalerite, Hematite, and magnetite. The list provided is just the most common and easily identified to point you in the right direction.  Start with the mineral type present. Are you dealing with silicate and carbonate rocks, granite or limestone usually, or sulfides that have pyrite for example? If you're not sure, are you seeing ...
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What Gives Petrified Wood Value?

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You must be wondering what characteristics or features give petrified wood value. That's why you're here. The author operates a rock and mineral shop, has been a geologist for over 15 years, and gives pointers below: SIZE: All else being the same a larger piece is worth more than a smaller one. That's easily first.  TEXTURE: The  appeal of Petrified Wood is that it is fossilized wood and preserves the woods texture and structure. Visible wood textures like rings, straight lines, the appearance of knots or branches, and variations in color that indicate inner and outer areas of the tree trunk are all components of Petrified woods value.  Some petrified wood looks like large pieces of chalcedony unrecognizable from Jasper from a totally different origin. These woods are sought after to polish because of their hardness and tendency to be non-porous. However in raw form they may be mistaken for Jasper from a hydrothermal origin. By weight all else being the same petrified woo...
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