 Selenium nanomaterials can exist in two distinct forms, thermodynamically unstable and metastable. Physicochemical synthesis produces thermodynamically unstable nanomaterials quickly, while biological synthesis produces metastable nanomaterials slowly. The biopolymer layer on biologically synthesized nanomaterials may be responsible for the slow rate of transformation. Additionally, phylogenetically diverse bacteria can convert selenium oxyanions into red amorphous selenium, which then transforms into the trigonal form of selenium. This form is used industrially as a semiconductor and alloy. It is unclear if biologically synthesized selenium nanomaterials have any biological function, or if they are simply a detoxifying and respiratory byproduct. Understanding the transformation of these nanomaterials could help recover them from secondary sources and use them in a sustainable manner. This article was authored by Miguel A. Ruiz Fresnida, Lucian C. Stecu, Guillermo Lasu and Lopez, and others. We are article.tv, links in the description below.