Austria: Philharmonic gold coin

Austria issued this mini-sheet of two stamps in 2014 to mark the 25th anniversary of the issuance of a Vienna Philharmonic gold coin. Both stamps are round when removed from their selvage. The blue (70 eurocents) features the organ in the Gold Hall and the red stamp (90 eurocents) shows various orchestra instruments. The stamp images are replicas of the coins obverse and reverse and utilize gold foil. The coin was issued in 1989 and is one of the most popular gold instruments in the European Union; Autria Post notes it is also very popular in Japan. The coins are known for their purity and exist in various denominations, including a silver coin. Though the stamp is marking the coin's issuance, the organ included on both stamp and coin is remarkable. Here is updated information from the Musikverein on the instrument. More images and a stoplist can be seen here.

Austria: St. Stephen's

Issued on 12 December 1946, this stamp is from a set of 10 semi-postal stamps. The additional price paid for each stamp aided in the reconstruction of the St. Stephen Cathedral in Vienna. There are actually currently three organs in the Dom: a choir organ from the 1950's; the west gallery instrument most recently updated in the 1960's, and a large instrument from 1991 in the nave. The instrument shown on this stamp is an older version of the west gallery organ, originally built in the 1880's by Walcker.  The organ is located in the west gallery and was re-built by the Kauffmann firm in 1960.
Shown at the bottom is the nave organ built by Rieger.