Is The Coso Artefact a Hoax?


The Coso Artefact is a perplexing archaeological find that has baffled scientists, researchers, and enthusiasts alike. Discovered in the 1961, this enigmatic object has sparked debates and speculation regarding its origin, purpose, and the implications it holds for our understanding of history.

This so-called OOPArt (out-of-place-artefact), a spark plug, was allegedly discovered encased in solid rock. The design of the spark plug, consistent with a bygone era, stirred bewilderment, suggesting usage before its entombment within the rocky matrix.

But, Is the Coso Artefact a Hoax or is it Proof of Advanced Ancient Civilizations?

Discovery and Characteristics

The Coso Artefact, an unmistakably modern relic, was stumbled upon during routine mineral prospecting in the Coso Mountains of California in the 1960s. The trio of discoverers, Wallace Lane, Virginia Maxey, and Mike Mikesell, cracked open what seemed to be an ordinary geode-like rock composed of a hardened sedimentary matrix, only to reveal the incongruity within – a spark plug encased in solid rock that was estimated to be over 500,000 years old.

During the cutting, a very laborious process, the blade wore out completely. Inside the stone he was cutting, Mikesell did not find the typical cavity of geodes, but rather a circular section of a very hard white material that appeared to be ceramic or porcelain; in the centre of the cylinder was a shaft of about two millimetres of bright and magnetized metal.

In addition to these deposits, the discoverers observed two non-magnetic metal objects embedded in the crust, which looked like a nail and a washer. Even stranger, the inner layer – disintegrated over time – was hexagonal and seemed to form a cover around the cylinder of hard porcelain. Inside, a layer of highly deteriorated copper surrounded the cylinder.

The artefact itself is a spark plug, a component commonly found in internal combustion engines. It consists of a ceramic insulator and a metal casing, with the electrode typically made of copper. The spark plug exhibits signs of wear, suggesting that it was used before becoming embedded in the rock.


The artefact gained popularity in the press covering paranormal phenomena in the early part of the following decade, and most reviews contained the information provided by the INFO Journal without delving deeper into the subject. In the late ’70s, a documentary series, “In Search of…,” hosted by Leonard Nimoy, dedicated part of a program to the Coso object. It is said that during filming, the object was misplaced, and it was never heard of again.

A 500,000 year old Spark Plug – Coso Artefact Mystery – Public Domain Clip

In 1999, attempts were made to trace its whereabouts, without success. Of the three discoverers, it is assumed that Lane and Mikesell are deceased, and Virginia Maxey was reserved and declined to make statements regarding the matter.

Very little is known about the early inspections. According to Virginia Maxey, they consulted with a geologist who examined the fossilized shells embedded in the sample and claimed that the piece would have taken at least 500,000 years to assume its current form. However, the identity of the geologist remains a mystery, and their findings were never published.

Another individual who conducted research on the artefact was creationist Ron Calais. Calais took photographs of it using both X-rays and visible light. The X-rays revealed that in the upper half of the artefact, there was some kind of coil or spring. In the other half of the artefact, it revealed what appeared to be a metal casing, presumably copper, covering the porcelain cylinder.


The discovery of a seemingly modern object in a geological formation dating back hundreds of thousands of years raised immediate scepticism and controversy. Critics argue that the Coso Artefact is a clear case of an out-of-place artefact (OOPArt), challenging conventional timelines of human history.

One hypothesis suggests that the spark plug may have been part of an ancient advanced civilization such as Mu or Atlantis that possessed technology similar to our own. Another theory posits that the artefact is evidence of time travel, suggesting that someone from the future accidentally left the spark plug in the past.

Another theory posits that rocks fossilize at a much faster rate than science believes, which would call into question the entire stratigraphy and current chronology of the planet; hence, Earth could be much younger than currently thought.

Ron Calais was a well-known creationist, and many manipulated or accidental OOPArts are promoted by these individuals precisely to validate hypothesis 3: Fossils do not indicate the actual age of the Earth, which is around 4,500 years as suggested by the Old Testament

Many researchers question the authenticity of the find, suggesting that it may be a hoax or a misinterpretation of the geological context.

Scientific Analysis

Over the years, various scientific studies were conducted on the Coso Artefact to determine its authenticity and understand the circumstances surrounding its discovery. Radiometric dating of the surrounding matrix has been inconclusive, providing a wide range of possible ages.

In 1999, Calais’s X-rays and diagrams were sent to various members of the American Spark Plug Collectors Association who, through different channels, unequivocally identified the object as a 1920 Champion spark plug.

What is frequently overlooked is that the Coso Artefact lacks any characteristics that would categorize it as a geode. The mere fact that the original discoverers were in search of geodes on the day the artefact was found doesn’t constitute sufficient evidence to label the artefact as a geode.

Geodes typically feature a thin outer shell made of dense chalcedonic silica and are filled with a layer of quartz crystals—neither of which are present in the Coso Artefact. Maxey, one of the discoverers, described the material covering the artefact as “hardened clay” and observed that it had collected a variety of pebbles, including a “nail and washer.” Analysis of the surface material using the standard Mohs scale indicates a hardness of Mohs 3, significantly softer than chalcedony.

In the Owens Lake area, there were mining explorations (with excavations and tunnels) in the early years of the 20th century. It wouldn’t be difficult, then, for an old spark plug from a gasoline engine to become covered in mud and sediments, including ancient shells. The nodule could then solidify with rust, water—possibly brackish, leading to the rapid oxidation of the iron casing—acquiring the consistency of sandstone.

Obviously, this is the simplest explanation, although since the artefact is missing, we cannot currently determine whether the material inside the geode is a modern cement or a Cenozoic sandstone.

Additional arguments concerning the ancient origin of the Coso Artefact centre around purported fossil shells encrusted on its surface. No petrological study was conducted on the sample, nor was a paleontological analysis of the shells carried out, which could have provided a more precise dating of the piece.

However, given that a nail and washer were also discovered on the same surface as the fossil shells, the strength of the inference regarding the artefact’s ancient age is notably diminished.

Mystery Solved

For a period of time following the investigation, the Coso Artefact disappeared. Pacific Northwest Sceptic Pierre Stromberg took an interest in this artefact and decided to look into it.

He contacted the Spark Plug Collectors of America, asking them to identify it, if possible. He received word back that the item had been positively identified as a 1920s Champion spark plug used in Ford Model T or Model A engines.

In April 2018, the family of one of the founders allowed Stromberg to conduct another examination by a geologist at the University of Washington. The initial conclusion was correct. The item is a 1920s sparkplug encased in iron oxide.

The Coso Artefact was on display at the Pacific Science Center in Seattle, Washington.


Despite the ongoing debates and speculations, the Coso Artefact has been proven to be either an elaborate hoax, or an honest mistake from the discoverers. But is definitely not a 500,000-year-old Spark Plug.

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