? About Coal

Hi,
Newbie here and have a question that I haven't seen posted yet here. I'm looking into getting a bulk delivery and was at a friends house who had a bulk load delivered about a month ago. I was noticing there are some pieces of coal(rice) which seem to have rust spots on them,not a lot but it's noticable enough, you can flake it away with your finger nail it's only surface. I was wondering is this normal for coal to have this. I'll have to ask him again where he ordered it from. Thanks for any info., have learned a lot from this site.

Joe

It is most likely iron, not that uncommon and should not effect the coals performance.