On July 21, 1967, the mineral galena was adopted as the official mineral of Missouri. Galena is the major source of lead ore, and the recognition of this mineral by the state legislature was to emphasize Missouri’s status as the nation’s top producer of lead. Galena is dark gray in color and breaks into small cubes. Mining of galena has flourished in the Joplin-Granby area of southwest Missouri, and rich deposits have been located in such places as Crawford, Washington, Iron and Reynolds counties. (RSMo 10.047)
The specimen pictured is from the Southeast Missouri Mining District in Reynolds County, MO.
Hypsibema missouriense is a type of dinosaur called a Hadrosaur or “duck-billed” dinosaur. It was a herbivore with jaws that contained over 1,000 teeth. Hypsibema had evolved specialized teeth to handle the tough, fibrous vegetation of the time. This dinosaur lived in Missouri during the Late Cretaceous Period. Hypsibema was first discovered in 1942 by Dan Stewart, near the town of Glen Allen, MO, and became the state’s official dinosaur on July 9, 2004 (RsMo 10.095) A reconstruction of Missouri’s State Dinosaur can be seen at the Bollinger Museum of Natural History in Marble Hill, MO. Source: Secretary of State webpage, http://sos.mo.gov/symbols/symbols.asp?symbol=dino
The crinoid became the state’s official fossil on June 16, 1989, after a group of Lee’s Summit school students worked through the legislative process to promote it as a state symbol. The crinoid (Delocrinus missouriensis) is a mineralization of an animal which, because of its plant-like appearance, was called the “sea lily.” Related to the starfish and sand dollar, the crinoid lived in the ocean that once covered Missouri. There are about 600 species alive in the ocean today. (RSMo 10.090) Source: http://sos.mo.gov/symbols/symbols.asp?symbol=fossil Note to people who live in Kansas: Kansas does not have an official state gem, mineral, rock, or fossil. If you would like to change this, you can contact one of your representatives and get one. I suggest Niobrara Chalk, as in Rock Chalk Jayhawks.
You’ve heard of petrified wood, but have you heard of petrified palm? It’s made from trees of the extinct genus Palmoxylon, which were very similar to palm trees. The process is the same: when the palms died, sometimes they would be covered by water or dirt before they rotted. Then, as groundwater flowed across the ground it carried dissolved silica which would fill the xylem and phloem inside the palm. The result is solid silica in the same shape as the plant. They usually turn out much smoother and more uniform than other types of petrified wood, and petrified palm can be cut, polished, and used as a semiprecious gemstone. It’s mostly found in the Catahoula Formation, Texas, and Louisiana (where it’s the state fossil).
As you can see, petrified palm’s distinctive round spots make great cabochons.
The thunder egg was declared the official state rock of Oregon in 1965, because there are quite a lot of them there. A thunder egg is a rounded nodule or geode with agate in the center. Thunder eggs can also contain quartz, chalcedony, crystals, or opal. The inside parts can be opaque or transparent – there are almost as many possible designs as there are agates. This unusual thunder egg shown above is from Oregon and has plume inclusions. Some thunder eggs are also geodes but this one is not a geode because it does not have crystal points. A more typical thunder egg would look similar, but with bands or a single color on the inner part.
Lake Superior Agates are a type of agate found near Lake Superior. They were carried across Minnesota by glaciers 10,000 years ago and are so common there that they have been Minnesota’s official state gemstone since 1969. Wisconsin and Michigan have some, too. Lake Superior agates are known for their red color which comes from iron oxide in the surrounding area. Most Lake Superior agates are banded agates, but a few are eye agates, some are “waterwashed” agates (called so because they have been naturally polished by the water on the beach, like sea glass), and, rarest of all, some of them weigh over 2 pounds.
I should also point out that if you ever go looking for agates, the ones in the field won’t be as colorful and they are easy to mistake for other rocks like granite or basalt. Most of the pictures of agates are of nice pretty polished slabs or cabochons, and that tends to give people unrealistic expectations. That’s why the photo shows Lake Superior agates before and after tumbling.
The Minnesota Department of Natural Resources was invaluable in writing this post. More information here: http://www.dnr.state.mn.us/education/geology/digging/agate.html