Galvanized fittings are commonly substituted in runs of copper tubing/brass fittings plumbing. Accordingly, even those houses that were not plumbed with galvanized are likely to still have some.

 

Full-size version

Note the smoother surface on the brass portion of the joined fittings.

Chemistry:

mg/kg Ca Cd Cr Cu Mn Pb S V
02_PFG26 7800 328 27 3280 0.21 2529 3400 27

High Pb and Cd are typical of metals derived from zinc plating on galvanized pipe. High Cu is from the adjacent brass; high S is likely a product of bacterial sulfate reduction.

 

Further images of corrosion scales on galvanized iron: utility 2

02_PFg26 - click for full size: galvanized+brass

 

02_PFg26 - brass side enlarged