dolostone

Illinois Now Has an Official State Rock. Here's What It Is

Dolostone is a sedimentary rock composed of dolomite and is similar to limestone

For decades, Illinois has had a state bird and even a state tree, but a state rock hadn't ever been designated, despite more than 30 other states having an official rock or stone.

However, that changed Monday.

At Lisle's Morton Arboretum, surrounded by a group of middle school students who played a pivotal role in the selection process as well as state legislators, Illinois Gov. J.B. Pritzker announced the official state rock - dolostone.

So, what exactly is dolostone?

Dolostone is a sedimentary rock composed of dolomite, which is made up of calcium magnesium carbonate, and is similar to limestone.

Dolostone underlies nearly all of Illinois, with the exception of some northern counties, and helps enrich soil by providing valuable nutrients, according to a previous news release from Illinois Senate Democrats.

It's also responsible for causing a major mineral rush in Galena in the early 1800s. To this day, you can visit dolomite prairies across Illinois, including two in Cook County.

Prairies both exist at the Sagawau Environmental Learning Center in Lemont and Theodore Stone Forest in Hodgkins, where plants are "extremely hardy" and the soil is just a few inches deep, with dolomite beneath, according to the Forest Preserves of Cook County.

So, how was dolostone chosen?

Upon learning Illinois didn't have a state rock, students at Pleasantdale School in Burr Ridge and Maplebrook Elementary School in Naperville took it upon themselves and decided that needed to change.

So, they interviewed regional geology scholars, visited museums, completed research and then got schools all across Illinois involved.

The students created a ballot with three choices, and dolostone was the winner.

"With hundreds of participating schools and thousands of votes from Carbondale to Rockford to Chicago, the choice was clear - dolostone emerged victorious," Pritzker said. "And it's no surprise dolostone, a specific form of limestone, forms most of our state's bedrock in the early 1800s."

The student involvement didn't stop with the voting process as they then worked with lawmakers to develop the legislation.

House Bill 4261, which sought to designate dolostone as the official state rock of Illinois, was first introduced in January and became a reality Monday, as Pritzker signed it into law.

Jennifer Lauermann, a Pleasantdale teacher whose students orchestrated the effort, said she was so proud of their effort and determination.

"The students, we'd started this project during a very crazy time, two years ago almost," she said Monday. "And I was teaching in a cafeteria and...there was a teachable moment that just exploded. A couple of kids started talking about rocks and pretty much, we really focused a lot of the year on geology. I'll never forget this."

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