Origin and model formation of the semi-precious Larimar stone in the Sierra de Bahoruco, Dominican Republic

Abstract

The investigation of the origin and evolution of the Larimar gemstone in the Dominican Republic has required the same scientific tools as used for some valuable metal deposits. This singular stone is the consequence of various processes that determine, firstly, the emergence of a pectolite without any aesthetic value, and then the conditions are modified until finally an outstanding product is obtained due to its coloration. The process in the Hispaniola Island begins in the Upper Cretaceous with basaltic lava emissions which create an oceanic “plateau” in the Checheses Larimar area, then emerge and, with the help of the deposition of organic materials, produce a hydrothermal alteration of the volcanic pile producing a pectolite concentration with a blue coloration suitable for use in jewelry. The Miocene-Pliocene tectonic changes its primitive structure until the current form is configured, whilst at the same time the hidden volcanic material crops out below a thick Eocene sedimentary series.