Diamond open access refers to academic texts (such as monographs, edited collections, and journal articles) published/distributed/preserved with no fees to either reader or author. Alternative labels include platinum open access, non-commercial open access, cooperative open access or, more recently, open access commons. While these terms were first coined in the 2000s and the 2010s, they have been retroactively applied to a variety of structures and forms of publishing, from subsidized university publishers to volunteer-run cooperatives that existed in prior decades.
In 2021, it is estimated that between 17,000 and 29,000 scientific journals rely on a diamond open access model. They make up 73%[1] of the journals registered in the Directory of Open Access Journals and 44% of the articles, as their mean output is smaller than commercial journals. The diamond model has been especially successful in Latin America-based journals (95% of OA journals[1]) following the emergence of large publicly supported platforms, such as SciELO and Redalyc. However, Diamond OA journals are under-represented in the major scholarly databases, such as Web of Science and Scopus. It is also noteworthy, that high-income countries "have the highest share of authorship in every domain and type of journal, except for diamond journals in the social sciences and humanities".[2]
In 2022, new national and international policies, such as the UNESCO recommendation on open science, and the Action Plan for Diamond Open Access promoted by the cOAlition S aim to support the development of non-commercial or community-driven forms open access publishing.