Coso artifact

Spark plug supposedly encased in a 500,000-year-old geode

The Coso artifact is an object falsely claimed by its discoverers to be a spark plug encased in a geode. Discovered on February 13, 1961, by Wallace Lane, Virginia Maxey, and Mike Mikesell while they were prospecting for geodes near the town of Olancha, California, it has long been claimed as an example of an out-of-place artifact. The artifact has been identified as a 1920s-era Champion spark plug encased in a concretion.

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