Question about that weird discoloration on old pottery shards

I was sorting through some field finds from a dig in Ohio last summer and noticed a greenish stain on about 15% of the pottery pieces. Turns out it was from copper in the soil, but I assumed it was from plant roots at first. Has anyone else run into this kind of mineral transfer on ceramics before?

2 comments

2 Comments

sean_murray6d ago

Was the copper stain concentrated along certain edges or surfaces, or did it look like it soaked through the whole piece? That might tell you if the pottery was sitting directly against something copper or if it was just the general soil chemistry.

tylerw724d ago

Yeah @sean_murray brings up a good point - was the stain mostly on one side or all over? I'm wondering if soaking the shards in distilled water would pull any of it out or if its pretty much permanent once it sets in.