Accessory fans better mark their calendars.  The Museum of Arts and Design’s MAD About Jewelry event returns next week, taking over the third floor at 2 Columbus Circle from May 6 to 9. Now in its 26th year, the annual showcase and sale will bring together 45 contemporary jewelers from 20 countries with Egypt and Slovenia being represented for the first time by Fatma Mostafa and Srečko Molk, respectively.  Earrings by Fatma Mostafa. Courtesy of the Museum of Arts and Design Bryna Pomp, MAD About Jewelry ’s director and curator, looked at nearly a thousand collections before selecting the final participants.…