I have a Hamilton case that is mark
Hamilton
hamilton Hallmark
QUALITY
PERMANENT
is it gold filled case or gold?

It is gold filled.

Thanks

Peter all of the gold colored cases I have ever seen in 50 + years of collecting have been gold filled. The word permanent means that the manufacturer warranted the case to wear like solid gold and as a practical matter the case might best be thought of as having extra thick gold plates over the brass plate in the middle and therefore likely to wear for many years without showing the underlying brass. The average owner could reasonably expect to get 30 years or more wear out of such a case and by the end of 30 years would have lost the receipt for the case or watch or be dead!They are not really permanent but they wear for many years.