A 3 foot long rock on Mars is now named Duluth thanks to similarities between the rock and city, plus Duluth native Roger Weins who led the ChemCam  instrument that found the rock.

The rock on Mars is a layered, sedimentary rock which is similar to Duluth which has a layered crystalline volcanic rock that forms the bedrock of the city according to an article on DNT. My favorite comparison is Duluth is nestled on the shores of Lake Superior, just like the rock on mars (now named Duluth) once lined the shore of a lake from the planet's past.

The rock was discovered while NASA's curiosity rover was exploring a slope called  the Murray Formation. The formation is a 1,000-foot-thick layer of rock formed from sediments that accumulated on the floor of an ancient lake.

It sounds like unique Mars rocks or spots on the planet will gt both official and unofficial names. All names will have to be approved by the International Astronomical Union to become official. I'm just happy that Duluth can be a tourist attraction on two planets now.