Moqui Marble 1 Piece Raw Minerals Stones Rocks Collecting Crystaltherapy (4)

Moqui Marble 1 Piece 7.5 gr - diameter mm 18 Raw Minerals Stones Rocks for Collection Crystaltherapy, only a piece, as in photo.
Also available in a lot of 3 pieces, at this link.

The Moqui Marbles are strange mineral also called Iron Balls, Balls Indian, Navaho Cherries or stones of shamans for their spiritual value in the traditions of the Native American Hopi regard to the worship of ancestors ("Moqui" translates as "the dead" in Hopi language).
Informally, they are called "Moqui marbles" because of the name proposed by the local Native American tribes Moqui. At first glance, seem artificial in nature: they are spherical in shape, the surface very rough and tough: they have a diameter ranging from 1-3 cm to about 20-30. The area in which these spheres were found is located in the desert of the United States between the state of Utah and northern Arizona, at the base of the Navajo Sandstone, a system of formations of sandstone blocks. The estimated age of these "balls" is between 120 and 190 million years ( Mesozoic).The outer part is composed of hematite and goethite (iron oxides), but inside is a very fine silica compound, type a sand -colored coral, while at the center of this there is a small ball of sandstone rock. These concretions have a wide variety of shapes and sizes, from the form of spheres to discs  buttons, spiked balls, cylindrical -shaped hollow tube, like other strange shapes. Some are as deep-groove ball with ridges around their circumference. Although many of these concretions are fused together like soap bubbles, many are found as isolated concretions. The evidence suggests that the microbial metabolism may have contributed to the formation of some of these concretions, which are considered terrestrial analogues of Martian hematite spherules that the rover Opportunity has found in the Meridian Planum on Mars.