Unitedstatesofamerica1 Posted January 25, 2016 Share Posted January 25, 2016 Thank you for your answers Quote Link to comment Share on other sites More sharing options...
rockhunter1620 Posted January 25, 2016 Share Posted January 25, 2016 Knowing yer in Penn. Prolly a clay stained limestone (sedimentary) w/calcite, water-worn=river cobble. Quote Link to comment Share on other sites More sharing options...
4meter Posted January 25, 2016 Share Posted January 25, 2016 I agree with rockhunter1620 that it is a water worn cobble, but I'm going with a metamorphic rock cobble with garnet fragments. In the last picture there is a piece of the brownish material that has the distinct shape of a garnet; also, there are apparently no cleavage plans visible, just fractures, like garnets produce. Best tests, place warm vineger on the white stuff & see if it fizzes, then do the same for the brownish stuff. If neither fizzes then it is not limestone or a carbonate, if it fizzes it is limestone or a carbonate. Check the hardness of the brownish stuff if less than 7/7.5 on the moh's harness scale it is not garnet. Quote Link to comment Share on other sites More sharing options...
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