In southern Utah, USA, where red sands give way to white and pink rocks, you can find thousands of small iron spheres that accumulate on mountain slopes and collect in "puddles" on the Navajo sandstone. The size varies from 3 mm to 7-10 cm in diameter. They are called moka stones or moka spheres.
Where did the name of the unusual stones come from?
The word "moki" was invented by the Hopi Indian people and means "dead".
Initially, the Spaniards who arrived on the still unexplored continent of America, the Hopi people called the "Moki Indians". In the early 1900s. their name was officially changed to Hopi.
According to one legend, the spirits of the Hopi ancestors come to earth at night and invade these iron spheres. Thanks to the wind, the moka stones come alive and race across the night sands of Utah. By morning, the spirits calm down and leave the mocha spheres, symbolizing the pacification of the departed.
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Moki stones are also called Navajo cherries, Navajo berries, Hopi marble, Moki spheres, and Shaman stones. Geologists classify them as nodules, dense globular stones.
What are moka stones?
Mocha stones are composed of sandstone containing a mixture of hematite and iron oxide. The core is surrounded by a hard shell of iron oxide minerals. Initially, sandstone accumulated about 180-190 million years ago in the form of sand dunes similar to the Sahara, which covered Utah, Arizona, Colorado, Wyoming, Idaho, Nevada and New Mexico. Particles of iron-rich minerals were cemented with quartz sand. Centuries later, iron was fused with sand particles, giving Navajo sandstone its amazing color and pattern.
Cross-section of a moka stone.
According to a recent study, the moka stones are no more than 25 million years old, and the samples found on the Paria Plateau in Arizona are only 300 thousand years old.
Martian blueberry
Such nodules are found not only on our planet! In 2004, NASA's rover discovered a nodule on Mars that scientists have named the Martian blueberry.
Martian blueberry.
It is believed that the Martian "berry" formed in the same way as their terrestrial counterpart, which indicates that Mars once had a wet surface. Indeed, water was necessary so that weak acids and hydrocarbons slowly dissolve iron in a liquid, which then seeps into underground waters. In turn, there the iron precipitated and cemented with sand.
Traces from the rover and "blueberries" - the color of the photo is distorted.
One of the differences between Martian blueberries and moka stones is that the former contains pure hematite, while moka stones contain only a few percent (sometimes the amount reaches 30%).
