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Lot 1060

Gem Dino Bone

27 May 2010, 13:00 EDT
New York

US$6,000 - US$7,500

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Gem Dino Bone

Allosaurus fragilis
Late Jurassic
Grand County, Utah

When superheated water passes through layers of rock due to geothermal activity, silica may be deposited in the porous marrow of dinosaur bone leading to complete agatization. The colorful agatized dinosaur bone from the remote Utah deserts is highly prized by collectors. The rarest type of agatization, called fortification agate, is illustrated by the present specimen. This process occurs when the superheated water blasts the center out of a bone, collapsing the bone marrow cell structure and completely infilling the cavity with mineral-laden silica or agate. As the agate cools, it forms layers in concentric rings with slightly different mineralogical components, creating the appearance of multiple rings or fortifications. The present specimen displays highly desirable deep red coloration. The large size of the marrow cells and the concentric layered rind of the bone indicates that it is from Allosaurus fragilis, as these characteristics are seen in meat-eating dinosaurs only. Measures 7 1/4 x 4 5/8 x 7/8in

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