I bought an old pan on ebay and I wish to know if it is enamelled or raw. Inside of pan has a black layer and a spot patch 6 by 3 cms of different layernature. How do I find out out if pan is raw cast iron. The thin black layer is difficult to identify. The seller says that pan is not enamelled. But I doubt it.
Enamel is usually white, though it may stain to a beige color.
Bare cast iron when stripped of its seasoning is steel grey. The first coat of seasoning will be a dull olive greenish brown, and each coat of seasoning will get darker. With use the seasoning will turn jet black as some of the oil polymers get toasted more over time.
If it is bare cast iron you will want to continue to wipe it down with oil after each use at a bare minimum of care.