He discovered tellurium in a sample of what is now known as calaverite. The Specter Sisters are named after minerals kermesite, berthierite, petzite and calaverite. These include natural gold tellurides, like calaverite and krennerite (AuTe), and sylvanite (AgAuTe). It is closely related to calaverite, which is more purely gold telluride with 3% silver. She is named for the mineral calaverite and her attack is "Dark Beauty". They include calaverite, sylvanite, nagyagite, petzite and krennerite. According to Schutte and DeBoer, those displacements also affect the coordination number of calaverite. Calaverite can be dissolved in concentrated sulfuric acid. Calaverite occurs as monoclinic crystals, which do not possess cleavage planes.