I just got back from an Alaskan cruise and there are more jewelry stores in their port cities than there are anywhere I have ever been. It was mind boggling. Your brooch could have sold for $200 in 1998. It looks handmade (judging from the pin clasp on back). I do not see any silver mark such as 'sterling' or '925'. I would take it to a local jeweler and have it appraised to find out the current approximate value.