My parents have collected an extensive Madrid depression glass set in the amber color. Pieces include cookie jar, pitcher and gravy boat with saucer. My father recently passed away and my mother is looking to sell the set or at least some of the pieces. The “prize” piece of their collection is the gravy boat as there were only 5 known pieces to exist. I’m looking to see what the current value is of the set or some of the key pieces other than the place settings.