black residue in tea kettle I have a stainless steel tea kettle, with sprayed on porcelain enamel.  The interior is sprayed black, with little white dots.  A very common design in the old ovens, and in many tea kettles.

When I wipe the interior dry, black comes off on the paper towel. This happens less if the kettle is emptied, but it still happens.

When I scrubbed the inside with barkeepers friend, the enamel itself came off, and left brown streaks.

What is the black that came off in the first place?  Is it enamel or oxide.  What is the brown streak?

** Update ** 

I had the tea kettle replaced by the manufacturer, but the same thing is happening again - not to the point where it would show up in a photo., but it is the black enamel finish with the white dots, and some of the white dots are gone. I was thinking of getting a water testing kit, and simply testing the water after its been sitting in the kettle to see what if anything is leaching. The reason I don't just get a plain stainless steel is that this is very, very, very pretty and that does matter to me. Not enough to ingest toxins though. Not sure what to test for, but I will order some kind of kit. It is not paint, it is sprayed on enamel - that's what the manufacturer said.
The black that originally came off is most likely mineral deposits. Those can easily be removed with vinegar or lime remover. 

The second part is a bit concerning and I would throw the kettle away since I don't think this is true enamel but possibly just paint. Enamel is very tough (think your teeth) and is hard to destroy. If you are able to scrub it off that is not a good sign. Then the brown underneath is problem rust from the metal. I would buy a new pot that is completely stainless steel.