World’s Oldest Spark Plug or Geological Anomaly?

Auto and history buffs know that the spark plug dates back at least as far as Edmond Berger’s never-patented, experimental design of 1839. But how about a 500,000-year-old spark plug? That’s how some explain the “Coso Artifact.” Found in 1961 by three rock hunters searching for geodes (rocks with hollow interiors studded with mineral crystals such as amethyst) in California’s Coso Mountains, the find has baffled geologists for decades – Is it the world’s oldest spark plug or just an unexplained geological happenstance?

X-ray image of the Coso Artifact

The Coso Artifact looked much like the fossil shell-encrusted geodes that the rock hunting trio often sought for their gem store. It wasn’t until one of the three, Mike Mikesell, took a diamond saw to the rock that something proved amiss. The rock split open, but instead of crystallized mineral, it revealed what looked like a porcelain cylinder surrounding a shiny metal rod. Also encased in the rock’s layers were what appeared to be a washer and a nail. Closer examination revealed that the porcelain was surrounded by a hexagonal casing, and an x-ray showed a tiny spring at one end.

In 1969, Ronald Willis of the International Fortean Organization, a nonprofit organization that promotes and facilitates research into unexplained phenomena, suggested that the threaded, corroded metal object might be an aged spark plug. The find might not be so curious save for one detail: According to geologists, the object’s rock encasement, assuming it was a bonafide geode, would have taken nearly half a million years to form. Even Berger’s very first spark plug would have been little more than a century old at the time. Willis’ report caught the attention of creationist organizations, since such a find might well force a revision of known history – at least the history of spark plugs – should the rock prove to, in fact, be a geode.

Three decades after the find, multiple organizations reopened investigations into the Coso Artifact. During the late 1990s, a researcher with the Spark Plug Collectors of America declared the object a 1920s-era Champion spark plug. So, how could a 40-year-old spark plug get inside a half-million-year-old rock? Skeptics say that the rock may not be a genuine geode but a much more recently formed rock. And even if it is a geode, it might have been covered in mud and clay sometime between the 1910s and 1930s, picked up a few hitchhikers as it rolled along and finally hardened in the California sun, baking the spark plug, nail and washer into its outer, much younger layer.

Unfortunately, we may never know for sure whether the Coso Artifact is in fact the world’s oldest spark plug and proof of ancient technology much more advanced than previously thought, or a simple geologic collision of the old and not-so-old. Attempts over the past few years to reach the Coso Artifact’s owner and its original finders have failed and no one else knows where the artifact is today. In any case, we at E3 Spark Plugs bet you’ll never look at a spark plug the same way again.