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MINERAL OF THE MONTH

June 2012 - Moqui Marbles

Moqui Marbles

The mineral of the month for this update is an unusual type of iron concretion called Moqui Marbles. These round rocks form in the Navajo Sandstone formations spread across northern Arizona, northwest Colorado, and Utah. Most are found in the numerous national parks in the area, so they can no longer be collected. I recently purchased a large quantity of moqui marbles that were collected legally many decades ago.

Navajo Sandstone

The wide range of colors exhibited by the Navajo Sandstone reflect alteration by groundwater fluids over the last 190 million years. The different colors are caused by the presence of varying mixtures and amounts of iron minerals such as hematite, goethite, and limonite. These minerals fill the pore spaces between grains of sand, causing the variation in colors in the sedimentary layers. The iron in these strata originally arrived via the erosion of iron-bearing silicate minerals. Variations in the type and proportions of precipitated iron oxides resulted in the different crimson, vermillion, orange, salmon, peach, pink, gold, and yellow colors of the Navajo Sandstone.

The Navajo Sandstone is also well known for its iron concretions. They are believed to represent an extension of Hopi Native American traditions regarding ancestor worship ("moqui" translates to "the dead" in the Hopi language). Informally, they are called "Moqui marbles" after the local proposed Moqui native American tribe. Thousands of these concretions weather out of outcrops of the Navajo Sandstone within south-central and southeastern Utah within an area extending from Zion National Park eastward to Arches and Canyonland national parks. They are quite abundant within Grand Staircase-Escalante National Monument. The Utah concretions formed around 25 million years ago when minerals precipitated from groundwater flowing through much older Navajo sandstone.

River of Moqui Marbles

The iron oxide concretions found in the Navajo Sandstone exhibit a wide variety of sizes and shapes including discs, buttons, spiked balls, hollow pipes, round spheres, and others. Although many of these concretions are fused together like soap bubbles, many more also occur as isolated concretions, which range in diameter from the size of peas to baseballs.

Moqui Marble Bin

These concretions are regarded as terrestrial analogues of the hematite spherules, called Martian "blueberries" or more technically Martian spherules, which the Opportunity Rover found on Mars.

Many people like to buy Moqui Marbles in pairs. The "male" spheres have ridges whereas the "female" spheres are smoother. Used together they balance the masculine and feminine energies. They are believed to be among the most energetic stones on earth. Their major properties are claimed to be cleansing, relaxation, and they provide a great boost to meditation.














Mineral of the Month Archives

May 2007: Rainbow Fluorite

June 2007: Lake Superior Michipicoten Agate

July 2007: Labadorite

August 2007: Rain Flower Agate

Fall 2007: Malachite

December 2007: Nepheline Syenite

January 2008: Native Copper

February 2008: Amazonite

June 2012: Moqui Marbles

March 2008: Lake Superior Agate

April 2008: Shadow Agate

May 2008: Apohpylite

June 2008: Ocean Jasper

Summer 2008: Marra Mamba Tiger's Eye

September 2008: Mohawkite

October 2008: Mexican opal

November 2008: Prehnite

December 2008: Picture Jasper

January 2009: Sea Shell Jasper

February 2009: Polychrome Jasper

March 2009: Selenite Desert Rose

Spring 2009: Coyamito Agate

July 2009: Obsidian Needles

August 2009: Goethite

September 2009: Banded Iron Formation

Fall 2009: Fairburn Agate

March 2010: Fossilized Dinosaur Bone

April/May: 2010 Kentucky Agate

June 2010: Nantan Meteorite

July 2010: Mookaite Jasper

Aug/Sept 2010: Polyhedroid Agate

Fall 2010: Ammonite Fossil

Winter 2011: Argentina Condor Agate

Spring 2011: Petrfied Wood

September 2011: Petoskey Stones

January 2012: Mary Ellen Jasper

March 2012: Mexican Crazy Lace Agate

September 2012: Chlorastrolite Greenstone

March 2013: Jacobsville Sandstone

August 2013: Unakite

November 2013: Skip-an-Atom Agate

April 2014: Tiger's Eye

September 2014: Black Corundum

February 2015: Condor Agate

June 2015: Petoskey Stone

November 2015: Slag

June 2016: Lake Superior Copper Replacement Agates

August 2016: Puddingstone


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Gitche Gumee Museum.
E21739 Brazel Street
Grand Marais, Michigan 49839

 


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