carbon or what?

[andz09]

just want to know if what is it we found a cement in the sea about 30 meters wide then we dig it after long digging we only found a charcoal pulvurized carbon i just want to know what is it can any one help?

 

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[piegrande]

Not without more information, most likely.

 

[piegrande]

Photo is best.

But as a general statement, there are some really smart people on TN at identifying things.