A predominantly-green metamorphic rock with blackish veining and/or mottling, maw-sit-sit was first discovered and identified by the renowned Swiss gemologist Eduard J. Gübelin during a 1963 expedition to northern Myanmar’s well-known jadeite deposits. It was subsequently named after a Burmese village located close to what was at the time, and still remains, the world’s only known source for the material.

As maw-sit-sit usually contains varying degrees of chrome-bearing green jadeite, it is sometimes also known by a variety of jade-related alternative names such as “chrome-jade” and “maw-sit-sit jade”. However, the primary constituent (~60%) within the material is the less well-known kosmochlor - a mineral that many prominent figures within the gemological industry believe should be officially designated as a “jade” alongside jadeite and nephrite. In addition, maw-sit-sit also contains small quantities of albite feldspar, eckermannite, chromite and natrolite.