Technically this could be under “Malaysia” since it was issued in conjunction with the 1990 World of Islamic Civilization Expo there.  Two cards are available, each mailed in Malaysia in 1991.  One has a Perak stamp and a rare double postmark from two different cities (Grade: 2, $6).  The other has a Pulau Pinang stamp (Grade: 1, $4).   Caption says this card portrays “Silver case containing sand sample from the grave of Prophet Muhammad S.A.W. Topkapi Museum, Istanbul.” One perforated edge on each card.