Nearly every state grass is shared by another state.
Nevada/Utah: Indian ricegrass, New Mexico/Colorado: Blue grama, Washington/Montana: Bluebunch wheatgrass, Wyoming/South Dakota/North Dakota: Western wheatgrass, Missouri/Illinois: Big bluestem
Wisconsin, Illinois, Rhode Island, and New Jersey all share the genus Viola (the violet) as the state flower.
Incredibly, every single state has a state soil. (Though not all have been legislatively established.)
That’s a lot of dirt.
Washington and Mississippi disagree on what petrified wood should be classified as. While Washington declared it as their state gemstone, Mississippi calls it their state rock.
Fewer states have declared a state mineral, AKA the gemstone’s less glamorous cousin. (Though California, Alaska, and North Carolina all share gold.)
All but 10 states (Kansas, Arkansas, Iowa, Minnesota, Indiana, the Carolinas, Rhode Island, and New Hampshire) do not have a state fossil.