Here are two views of a thick rind of hematite on a rock (sawn face on right).
A most excellent example of a hematite coating precipitated onto a host rock. Thanks, Daniel.
All 8 of these hematite concretions were found in the country of Georgia.
All of these are all from China.
I found this photo on e-bay. The rock was offered for sale as “0.8 lb Meteorite Specimen from Nandan, China!” The “Buy It Now” price was $295. It looks like a hematite concretion to me. Many hematite concretions start out as masses of cubic pyrite (iron sulfide) crystals that oxidize to hematite (iron oxide). That’s what this one looks like.
