sedimentary
Moqui Marbles
Iron Oxide Concretion (Hematite/Goethite)
Hardness: 5-6 (outer shell), color: dark brown to black exterior with sandy interior, luster: dull to sub-metallic, structure: spherical/ovoid, cleavage: none.
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Physical properties
Hardness: 5-6 (outer shell), color: dark brown to black exterior with sandy interior, luster: dull to sub-metallic, structure: spherical/ovoid, cleavage: none.
Formation & geological history
Formed in the Jurassic Navajo Sandstone (approx. 190 million years old) through groundwater precipitation of iron minerals around a nucleus, often a sand grain or organic matter.
Uses & applications
Primarily used for geological collecting and metaphysical purposes. Occasionally used as decorative stones or in historical artifacts.
Geological facts
Also known as 'Shaman Stones,' they are found in the American Southwest. NASA has studied similar structures on Mars known as 'Martian Blueberries,' suggesting water once flowed there.
Field identification & locations
Identify by their distinct spherical shape and heavy iron shell. Common in Utah's Grand Staircase-Escalante. Note: Collecting them inside National Parks is illegal.
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