There are some diva holiday albums that float to the top as the most famous- we’ll hear some of them as part of “December Divas.” Then, there are the more unsung (pardon the pun) ones, and finally, there are the obscure ones. And who would’ve ever thought that something produced by the late, great Beverly Sills would ever end up in a pile of obscure anything? Well, here we are, dusting off “Beverly Sills Singing Songs for Christmas 1955,” a 12-minute album that, according to Beverly Sills Online, was released as a promotional gift from the architectural firm of Fordyce and Hamby. Sills was 26 and just on the cusp of her stardom and presence at New York City Opera when she recorded the 5-track album. While hard copies of the album are rare to come by, it is widely available in digital format. The selections are all religious in nature, though the spare musical treatment of the pieces (only voice and organ, deftly played by Howard Kubik) keeps the album from sounding syrupy. At the time of the recording, Sills lacked some of the incisiveness that characterized her mature career, though the voice is fresh and gleaming, poor recording quality aside. The album’s first selection, “Gentle Mary,” an English translation of a charming Catalan folk song, is the high point. Sills is at her most expressive and has great support, both from the material and from Kubik. Her rendition of “O! Holy Night” (here called “Chantique Noel”) is a prime example of how Sills was not yet fully formed as an artist- not a bad take on the piece at all, but a take that lacks any of Sills’ signature warmth and spark. Similar is “Little Child Jesus,” which, though it has some excitement, is uneven in treatment, tone, and tempo. In fact, it is the slower tracks that have more success on this album. Sills lavishes more time and attention of a moving “Bless This House” that brings the album to a satisfying conclusion. It’s not a perfect Christmas album (and it could, arguably, be even better if there were more tracks on it), but it’s a charming collection of secular Christmas music and a significant historical document from the career of a great singer.