On View in the Grand Gallery
Some of the trilobite fossils on display are hundreds of millions of years old—but they are so exquisitely preserved that the animals seem almost alive, crawling along the seafloor. Trilobites are marine arthropods, a group that also includes insects and horseshoe crabs. The first trilobites evolved some 520 million years ago, during the Cambrian Period, when our planet was mostly covered by water and life forms were becoming more complex and more diverse. Scientists have discovered more than 20,000 species of trilobites, which went extinct 225 million years ago.
This exhibit is made possible thanks to Martin Shugar, M.D. and Andy Secher.
With hundreds of sword-like, metallic blue-gray crystals sprouting from a rocky base, the 1,000-pound stibnite on display in the Grand Gallery is one of the Museum's most spectacular mineral specimens. Stibnite (Sb2S3), a compound of the elements antimony and sulfur, occasionally forms nests of delicate, six-sided crystals, but examples this large and intricate are exceedingly rare. This unique specimen was spared from destruction by alert miners in the Wuning (Wuling) antimony mine in Jiangxi Province of southeastern China. Stibnite is most commonly pulverized and heated to extract the antimony and make flame retardants and engine bearings.
This two-foot-diameter fossil, known as an ammonite, is a large and particularly rare example of a marine animal that was once one of the most common invertebrates in the oceans. Ammonites became extinct around 65 million years ago, the same time as most non-avian dinosaurs. Its spectacular coloration is the result of millions of years of high temperatures and pressures acting on the animal's shell to create a gemstone known as an ammolite.
A two-foot-long slice from a jadeite jade boulder provides a spectacular window into the dramatic process that formed this highly prized type of jade. This jadeite started as a small vein, or fracture, over 12 miles underground that was wrenched apart by the collision of two tectonic plates over 35 million years ago. During the shakeup, mineral-rich fluids rose into cracks in Earth's mantle and deposited jadeite rock. As the tectonic plates continued to rub against one another, the veins of jadeite broke and reformed again and again, producing the remarkable emerald green and white swirls. The polished 55-pound slab was recovered from northern Burma.