sedimentary
Moqui Marble
Ironstone Concretion (Goethite/Hematite)
Hardness: 5-5.5 | Color: Dark brown to black outer shell with tan/yellow sand interior | Luster: Dull to sub-metallic | Crystal Structure: Amorphous/Microcrystalline | Shape: Spherical to sub-spherical
- Hardness
- 5-5
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5-5.5 | Color: Dark brown to black outer shell with tan/yellow sand interior | Luster: Dull to sub-metallic | Crystal Structure: Amorphous/Microcrystalline | Shape: Spherical to sub-spherical
Formation & geological history
Formed as iron oxides (hematite and goethite) precipitated from groundwater around a nucleus in porous sandstone, often during the Jurassic period (Navajo Sandstone).
Uses & applications
Primarily used as metaphysical stones ('shaman stones'), geological educational specimens, and for decoration/collecting.
Geological facts
Identical spherical iron concretions have been discovered on Mars, where NASA scientists nicknamed them 'blueberries.' Their presence suggests water was once present.
Field identification & locations
Identify by their distinct spherical shape, dark iron-based shell, and tendency to occur in groups scattered across desert sandstone landscapes. Commonly found in Utah, USA.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary