AN OUTSTANDING SLICE OF GEM DINOSAUR BONE. ...

Description

AN OUTSTANDING SLICE OF GEM DINOSAUR BONE
Allosaurus fragilis
Late Jurassic - 144-156 million years old
Grand County, Utah
Dinosaur bone can fossilize in many ways, but when superheated water passes through layers of rock due to geothermal activity it can deposit silica in the porous marrow of the dinosaur bone leading to complete agatization. These agatized bones are essentially infilled with the mineral quartz or silicon dioxide which can pick-up a variety of colorful minerals that were dissolved in the superheated water - this mechanism is commonly referred to as "hydrothermal deposition". These colorful agatized dinosaur bones are highly prized by collectors who avidly search for them in the remote Utah deserts. The rarest type of agatization is called a "fortification agate"; this occurs when the superheated water blasts the center out of a bone like a high pressure jet, collapsing the bone marrow cell structure and completely infilling the cavity created with mineral-carrying silica or agate. As the agate cools, it forms layers in concentric rings with slightly different mineralogical components, creating the multiple rings or fortifications of "fortification agate". The most prized colors by collectors are red and yellow. Here we have an exceptional blood-red "fortification" specimen of incredible beauty.
We can definitively identify this bone as coming from Allosaurus because of the large size of the marrow cells near the center of the bone and the concentric layered rind of the bone, which is characteristic of theropod (meat-eating) dinosaurs only. An exquisite example of nature's art measuring 5 x 4 inches by 2 inches thick.

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