This year, however, the man chose to find out everything about the mysterious rock, so he took it to Mona Siberscu at Central Michigan University's College of Science and Engineering.
The rock, which at the time was used to prop open doors, was taken by the farm's new owner when he eventually sold the property, and only just got around to seeing if it was actually a true meteorite.
"For 18 years, the answer has been categorically "no" - meteor wrongs, not meteorites", Sibescu stated in a assertion from the university on Thursday.
And geologist Mona Sirbescu said she "could tell right away that this was something special".
Even though Dr. Sirbescu knew exactly what it was, it had to be sent to the Smithsonian Museum for verification, it wasn't until Thursday word came back it definitively is a meteorite, the 6th largest ever found in MI. "It's the most valuable specimen I have ever held in my life, monetarily and scientifically".
The man contacted Sirbescu, who identified the rock as a meteorite composed of about 88 percent iron and 12 percent nickel.
After analyzing the rock themselves, the Smithsonian Institution researchers confirmed the Sirbescu's first results. He says the farmer who sold him the property told him it landed in his backyard in the 1930s.
The farmer said that it had come down onto the property in the '30s - "and it made a heck of a noise when it hit", the new owner recalled him saying, according to CMU's statement.
David says his kids took the space rock to "show and tell" at school.
"I said, 'Wait a minute. I wonder how much mine is worth", he said.
More tests are being conducted to see if the meteorite contains rare elements.
The meteorite's anonymous owner is promising to donate 10% of sale proceeds to the university.
The Smithsonian museum has valued the meteorite, which they named the Edford, at $100,000.
In January, the man made a decision to learn once and for all about the value of the doorstep.