"Intended use" is the linchpin of any appraisal. To perform an appraisal properly, you must know what it's for and include the reason on the report itself. Why is the issue of intended use so important? The story behind a recent trial in Florida provides a dramatic answer. In July 1993, Manuel Marcial, president of Key West, Fla.-based Emeralds International, showed an emerald-and-diamond ring to a vacationing couple, Meredith Gorman and Steven Zinn of Sarasota, Fla. The jeweler told the couple that the emerald, a 1.7-ct. pear shape, was from the Chivor mine, one of the more important mines in Colombia. The ring was priced at $6,900, and the couple needed more time to decide. Marcial gave them a business card on which he'd written the information about the ring. Zinn contacted Marcial on Aug. 28, 1993, and made a $1,000 deposit on the ring. He paid the final installment on Dec. 5, 19