Guys, "true contralto" is probably something that exists only in the minds of critics and public-relations people. They have to create the impression that certain opera stars are extraordinary singers in order to get people to pay those high prices to attend.

The world of opera is rigid and ritualized. The contralto is the one who's not going to get the guy. She has to sing low and sing dark. She gets years of training so she can sound like every other contralto. When she does, the critics can tell she's "good."

Maybe newly-written operas are different.