I have a bracelet that I would like to have appraised. It's about 20 years old, purchased from Mayors. It's a tennis bracelet, gold, with rubies, diamonds, emeralds and sapphires. It looks to be about 2 ct t.w. How do I go about finding a reputable appraiser? What should I know before visiting? Do I need anything else besides the bracelet (it was my grandmother's)? Does it cost anything? Any advice would be great. TIA!