pyrite spheres from sediments. These spheres have a mean diameter of about 

 10 microns, and have been identified as pyrite on the basis of solubility tests 

 and X-ray diffraction patterns. The spheres are formed in recent sediments, 

 as evidenced by their occasional presence inside dead plant and animal cells 

 in the sediment. Pyrite spheres were isolated from a Spartina salt marsh 

 deposit on Sapelo Island, Georgia. The method of isolation was based on the 

 separation of heavy and light minerals in tetrabromoethane (density i 2.95). 

 The heavy mineral fraction mostly consisted of the pyrite spheres. 



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