If y'all want to hear a true contralto, dig out your old Christmas carol albums or Handel's Messiah by the Robert Shaw Chorale and listen to Florence Kopleff (she sings a solo of The Cherry Tree Carol, among other things. She also serves as the entire alto section of the group, against five sopranos, four tenors, three baritones and a bass).

One reason for the "rarity" of true contraltos is that less music is written for contralto soloists, so they don't come to light. Also, it has been fashionable here in the San Francisco Bay Area for some time to cast mezzo-sopranos in alto roles. A great pity.