sedimentary
Petrified Dinosaur Bone (Gembone)
Agatized Dinosaur Bone
Hardness: 6.5-7 (Mohs scale), Color: Red, brown, and gray hues, Luster: Vitreous to waxy after polishing, Structure: Preservation of trabecular (spongy) bone cells replaced by silica/quartz, Specific Gravity: 2.6-2.7
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Red, brown, and gray hues, Luster: Vitreous to waxy after polishing, Structure: Preservation of trabecular (spongy) bone cells replaced by silica/quartz, Specific Gravity: 2.6-2.7
Formation & geological history
Formed during the Mesozoic Era (Jurassic or Cretaceous periods) through the process of permineralization. Mineral-rich groundwater deposited silica into the pores of decaying bone, eventually replacing the organic material with chalcedony or agate.
Uses & applications
Primarily used for lapidary work, jewelry making (cabochons), and as a collector's specimen due to its unique cell patterns and historical significance.
Geological facts
Cells in gembone are often large enough to be seen with the naked eye. In 'gembone' quality specimens, the distinct cellular structure of the dinosaur bone is perfectly preserved in colorful agate.
Field identification & locations
Identify by looking for characteristic 'honeycomb' or cellular structure on the surface. Commonly found in the Morrison Formation of the Western USA (Utah, Colorado, Wyoming). Collectors look for vibrant colors and distinct cell preservation.
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