Coso artifact

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 stone matrix containing the artifact is not a geode but a concretion that can be explained by natural processes that can take place over decades or years, not millennia.

[3] In a letter to Desert Magazine of Outdoor Southwest, a reader stated that a trained geologist had dated the nodule as at least 500,000 years old.

[6] There are several pseudoscientific theories for the artifact's origin,[1] among them: An investigation by Pierre Stromberg and Paul Heinrich, using x-rays taken of the object,[3] with the help of members of the Spark Plug Collectors of America, identified the artifact as a 1920s-era Champion spark plug, widely used in the Ford Model T and Model A engines.

As of 2019[update], the artifact resides at the Pacific Science Center in Seattle, where it is shown in an exhibition called "What Is Reality?