The International Organization for Standardization (ISO) has published standard ISO/TS 21236-1:2019, “Nanotechnologies — Clay nanomaterials — Part 1: Specification of characteristics and measurement methods for layered clay nanomaterials.” The standard specifies characteristics to be measured of layered clay nanomaterials in powder form and chemically modified ones and describes their relevant measurement methods. According to the standard abstract, there are numerous industrial applications for layered clay nanomaterials. Given the wide range of clay nanomaterial applications, various fundamental characteristics play undeniable roles. According to the abstract, these characteristics are measured and reported by the provider of the layered clay nanomaterials. ISO states that the determinations of these fundamental and basic characteristics will facilitate the communication between sellers and buyers of these nanomaterials for different applications. These characteristics are considered for all industrial layered clay nanomaterial applications, such as nanocomposites, paper, ink, purification, and catalysts. In addition to fundamental characteristics, some other optional characteristics of layered clay nanomaterials are measured and reported subject to the agreement between sellers and buyers. ISO notes that the standard does not deal with health, safety, and environmental issues.