Vocally, she is best described as a soprano, though later in her career her tessitura descended to that of a mezzo-soprano.
en.wikipedia.org A true operatic contralto is extremely rare, so much so that often roles intended for contraltos are performed by mezzo-sopranos.
en.wikipedia.org The collection was completed in 1841, and initially composed for tenor, and mezzo-soprano, later arranged for baritone, contralto, or soprano, and piano.
en.wikipedia.org They tease, ponder, reminisce, philosophize and invent parables, and she sings them in a plush, changeable mezzo-soprano that usually holds a kindly twinkle.
en.wikipedia.org Male singers can be classified by vocal range as bass, bass-baritone, baritone, tenor and countertenor, and female singers as contralto, mezzo-soprano and soprano.
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