The Larimar deposit known so far is located in the Los Chupaderos area of the Los Checheses Section, about 7 kilometers northwest of La Ciénaga and 10 kilometers southwest of Barahona. This deposit is a basic volcanic complex, consisting essentially of intensely altered porphyritic andesites and basalts, at least in the outcrop area, and surrounded by thick mantles of Eocene limestone that have been strongly brecciated as a result of the upward movement of the volcanic complex.

Larimar occurs in the form of small concretions that fill cavities produced by the escape of gases at the time of basalt crystallization. These concretions generally tend to be oval and concentric with a core that is often white due to the concentration of calcium oxide (CaO).