Moqui Marbles

Photo by Shinichi Kato. To see more of his outstanding mineral photo collection, click here. moqui marble

As far as I can determine, little is actually known about the origins of Moqui Marbles. In the United States, most of them come from the Navajo Sandstone Formation in the state of Utah. These mostly smooth, eliptical or round balls of compacted sandstone are encased in a "shell" of hematite (an ore of iron). They are also referred to as "Moqui Balls", "Thunderballs" or "Shaman Stones" and come in a variety of sizes ranging from that of common marbles to that of a baseball. The photograph above provides an excellent example of the structure of Moqui Marbles although the color is not always as contrasting as shown here.

In the US, they are commonly called Moqui Marbles after the Moqui Indians who inhabited the lands where they are found. Found during the excavation of ancient ruins around the world, some archeologists believe they have been used for centuries by Shamans and other mystics. There are various theories about how they were formed. Some geologists believe them to be ironstone concretions formed 130 to 155 million years ago.

According to one source, in the Hopi language, the word "moqui" means "dearly departed one." Legend says that the departed ancestors of the Hopi Indians of the Southwestern United States played games with these "marbles" in the evening when spirits are allowed to visit the earth. When the sun rises they must return to the heavens so they leave the marbles behind to let relatives know they are happy and well.

Moqui Notes of Interest

Dave Crosby, a geologist who has been doing some research in the Escalante, Utah area where Moqui Marbles are found in the US provides some additional information about another theory of the source of Moquis. Dave believes that the marbles were formed as the result of a meteor impact in the area. He wrote:

"This material was formed in an impact site 12 miles east of Escalante, UT in an area known as 'Big Spencer Flat'. The 'marbles' are composed of millions of molten spheres condensing on sand grains that bumped into and joined with other grains to form small spheres that joined with others to become even larger, with the hematite/silica coating always moving to the outside, but leaving a thin coat on most sand grains inside. Some larger spheres cooled below the melting point during this process, so all steps of it can be seen. Some 'marbles' landed in sand, others in limestone, and some have joined in almost every way imaginable. Most of the crater has eroded away, but the remnants of dikes created in the impact are still visible.
"The principle collecting area is in the new Escalante National Monument, but material was deposited on top of eroded Navajo Sandstone as far as Lake Powell. I have yet to determine if reports from Scofield Reservoir could be the same formation, or a different impact. I am sure the same process has produced 'Indian Paint Pots' in sandstones from many time frames all around the world, and are much like 'tektites.'"

7/27/01 update note : For those of you interested in Moquis, I received the following note from Dave regarding the composition of a moqui marble from Garfield County, Utah which has been a primary source of Moquis in the past:

Source: Doelling [Geology and Mineral Reserves of Garfield County, Utah - Utah Geological and Mineral Survey Bulletin 107, 1975 Page 156] states:
"A complete ironstone concretion [from Big spenser Flats] was analyzed and found to contain 15.2% iron [amazing when you consider most of the iron is usually only in the outer shell!]; a spectrographic analysis showed that the major constituents were iron and silicon [these terms should have been reversed as about 83% is silica] . Additional elements included aluminum and manganese in the 0.01 to 0.1 percent range: zinc, titanium, magnesium, calcium, sodium, potassium, zirconium, and barium in the 0.01 to 0.1 percent range; and traces of lead, copper, vanadium, chromium, nickel, cobalt, and silver."

8/20/01 update note: After a recent visit to a major Moqui Marble site, Dave has changed his view about the formation of Moquis. He writes:

"Robert Eves - a Geo-chemist from the University of Southern Utah - and I went to Big Spencer Flats yesterday, and demolished my previous suppositions. There are no (meteor) impact features at the site."
"We examined three different layers of the Navajo Sandstone. In areas where there was very little evidence of groundwater we found tiny iron spheres around grains of sand, seperated at distances varying from 2 to 3 inches apart. In areas where there was evidence of a lot of groundwater, the spheres had joined together in thick sheets of iron oxide/sand. In intermediate layers we found the Moquis."
"My new theory is the following":

1. Rainwater dissolves iron along with other minerals and transports these ions in the groundwater through the Navajo Sandstone.
2. As the groundwater pressure diminishes, the ions are deposited throughout the sandstone, but more predominantly along the bedding planes that conveyed the greatest amount of moisture.
3. The next rainstorm brings more iron ions that link with the previously deposited material, forming tiny spheres around the closest individual sand grains.
4. As more iron ions arrive the spheres continue to grow [around existing grains of sand] until they make contact with the surrounding spheres, then they grow together.
5. In broad water transport zones the iron spheres join into sheets of ironstone that deflect future flows into the surrounding bedding planes, trapping pockets of sand, often producing amazing massive structures.
6. In areas where the growing spheres are evenly deposited throughout the sandstone, the spheres eventually join with surrounding spheres to encompass spherical areas, eventually becoming large spheres that are now impermeable to water. Any new ions must collect on the surface, thickening the outer shell. There may be repelling ions of other materials involved that would force the forming of outer shells that form around previously formed spheres.
7. If groundwater pressure is just right, tubes are formed rather than spheres.
8. Intermediate zones produce both sheet and sphere features, producing the "flattened," or "flying saucer" shaped nodules.

To contact Dave about his theories on the origin of these unique geological oddities, e-mail him at

We'll keep you posted as we receive new or updated information about Moquis from Dave or other sources we run across.


Page last updated on 12/01/01