Herz aus Glas (subtitled "Singet, denn der Gesang vertreibt die Wölfe" [German for "Sing, for singing drives away the wolves"], French "Cœur de verre") is the ninth album by Popol Vuh.

It was originally released in 1977 on Brain Records.

In 2005 SPV re-released the album with two bonus tracks.

This album was released as the original motion picture soundtrack of Heart of Glass (Original German title: "Herz aus Glas", French title "Coeur de verre") by German director Werner Herzog, but in fact only two tracks ("Engel der Gegenwart" and "Hüter der Schwelle") were actually featured in the film.

Recorded at Bavaria Studios, Munich Engineered by Hardy Bank, Frank Fiedler and Robert Wedel Produced by Florian Fricke and Renate Knaup