Also called "Stefilia's Stone", is a rare blue variety of the silicate mineral pectolite found only in the Dominican Republic, in the Caribbean. Its coloration varies from white, light-blue, green-blue to deep blue. larimar is a slightly soft stone with a hardness of 4.5 to 5 on the Mohs scale, approximately the same as apatite, sphene and turquoise. Larimar has a vitreous to silky luster. Quality grading of Larimar is according to color; white is low quality and volcanic blue is the highest quality.
The Dominican Republic's Ministry of Mining records show that Father Miguel Domingo Fuertes Loren of the Barahona Parish requested permission on 23 November 1916 to explore and exploit the mine of a certain blue rock that he had discovered. Pectolites were not yet known in the Dominican Republic, and the request was rejected.
Miguel Méndez and Peace Corps volunteer Norman Rilling rediscovered Larimar in 1974 on a beach at the foot of the Bahoruco Mountain Range, the coastal province of Barahona. Natives believed that the stone came from the sea, and they called the gem Blue Stone. Miguel took his young daughter's name Larissa and the Spanish word for sea (mar) and formed Larimar, to suggest the colors of the Caribbean Sea where it was found. The few stones that they found were alluvial sediment, washed into the sea by the Bahoruco River. An upstream search revealed the in situ outcrops in the range and soon the Los Chupaderos mine was formed.
Larimar is a type of pectolite or a rock composed largely of pectolite, an acid silicate hydrate of calcium and sodium. Pectolite is found in many locations, but larimar has a unique volcanic blue coloration, which is the result of copper substitution for calcium.
Miocene volcanic rocks, andesites and basalts, erupted within the limestones of the south coast of the island. These rocks contained cavities or vugs which were later filled with a variety of minerals, including the blue pectolite. These pectolite cavity fillings are a secondary occurrence within the volcanic flows, dikes, and plugs. When these rocks erode, the pectolite fillings are carried down the slope to end up in the alluvium and the beach gravels. The Bahoruco River carried the pectolite-bearing sediments to the sea. The tumbling action along the streambed provided the natural polishing to the blue larimar, which makes them stand out in contrast to the dark gravels of the streambed.
There is no official grading standard for Larimar. The local industry, has several ways they grade the stone primarily by using A, AA, AAA scale AAA being the best. Outside of the local market we take in consideration more precise factors like Color, pattern and size when buying rough Larimar. For Cabochon we consider the same as the rough but also the design (cut) and luster.
Fakes and Inposters
The mines are really difficult to access and the area may be closed off 5 months of the year due to the torrential rains & hurricane season making it very unsafe to dig. There are dealers ON eBay that sell larimar quarts, this are imposters. Although they might look similar these type quarts are died to look like larimar. Also lab created larimar has surfaced in the past few years through China, fortunately for us they have not come close to looking like the real Larimar.