- Santa Eulalia District, Mun. de Aquiles Serdan, Chihuahua, Mexico
- Cabinet, 14.7 x 3.9 x 2.3 cm
A long (11 cm), slender crystal of gypsum has been entirely replaced by goethite, retaining the form of the gypsum crystal; the center is hollow, and the gypsum appears to be completely gone. This long crystal is attached to a larger, thicker pseudomorph which is presumably of the same origin, with only leafy sheets of goethite remaining.