DETROIT – It's not mud, dirt or some type of extraterrestrial material that will give you super powers - it's actually something way cooler.
A few Michiganders stumbled upon what looked to be black sand on a beach near Holland, Michigan last week.
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The sand was meshing with the brown sand and it actually made for a cool photo. See below.
Tara Stacey, a Metro Detroit native, said her and her two friends were confused.
"The entire beach wasn't black sand, just certain parts," Stacey said. "We were trying to figure out if it was silt or something."
We decided to check with the Michigan DNR's mineral office - and here's what we found.
The black sand is likely magnetite - a magnetic mineral that occurs in almost all igneous and metamorphic rocks. The black sand found could be magnetic, if dried.
The black sand found on the shore on Lake Michigan is not unheard of.
A study conducted on the Lake Michigan shore in Milwaukee found several instances of magnetic sands popping up on beaches. Here's some info from the 2004 study:
Magnetic susceptibility measurements were used as the indicator of the amount of magnetic material in the sand samples collected over a number of years along the west coast of Lake Michigan near Milwaukee. There seems to be only small variations in the amount of magnetic material on the present beaches over almost 100 km of the shoreline.
The high concentration of magnetic sands (up to 20%) found at two beaches in 1998-99 appears not to be related to the ephemeral streams that cross the beach but more likely the result of the erosion of bluffs during high lake levels in 1998-99. The erosion provides new sources of sediments to the littoral zone, which apparently includes quantities of heavy minerals, including magnetite.
Small concentrations of black sands are common on the Great Lakes. On the Wisconsin shoreline of Lake Michigan they are composed primarily of high-density oxide and silicate minerals such as magnetite, illmenite, hematite, amphiboles, pyroxenes, and garnets. This is based on microscopic observations of the dark minerals separated from the sand with a Franz Isodynamic separator.
These minerals are common constituents in igneous and metamorphic rocks and may become part of the sand from the mechanical weathering of the source rocks during glaciation or from the abrasion of rocks in the surf zone. Black sands concentrate in the near shore because higher density particles have different hydraulic properties in the surf zone than the less dense quartz and feldspar (Komar and Wang 1989). These concentrations are essentially lag deposits or placer deposits.
It would not be unusual to have concentration of black or magnetic sands of about 2% because this is a typical concentration in many igneous rocks. However, concentrations as high as 20%, as noted in 1998-99 at selected beaches, are anomalous.
The DNR says it's likely the explanation for the black sand, but they would need to test how magnetic the sand is to be absolutely certain.