Larimar is the tradename for a rare blue variety of the

silicate mineral Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...

pectolite Pectolite is a white to gray mineral, Na Ca2 Si3 O8(O H), sodium calcium hydroxide inosilicate. It crystallizes in the triclinic system typically occurring in radiated or fibrous crystalline masses. It has a Mohs hardness of 4.5 to 5 and a specif ...

found only in the

Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares with ...

, around the city of Barahona. Its coloration varies from bluish white, light-blue, light-green, green-blue, turquoise blue, turquoise green, turquoise blue-green, deep green, dark green, to deep blue, dark blue and purple, violet and indigo and the larimar can come in many varieties and color mix.Woodruff, R.E., 1986
''Larimar, beautiful, blue and baffling.
' ''Lapidary Journal'', 39(10), pp.26-32.

History

The Dominican Republic's Ministry of Mining records show that Father Miguel Domingo Fuertes Loren of the Barahona Parish requested permission on 22 November 1916 to explore and exploit the mine of a certain blue rock that he had discovered.

Pectolite Pectolite is a white to gray mineral, Na Ca2 Si3 O8(O H), sodium calcium hydroxide inosilicate. It crystallizes in the triclinic system typically occurring in radiated or fibrous crystalline masses. It has a Mohs hardness of 4.5 to 5 and a specif ...

s were not yet known in the Dominican Republic, and the request was rejected. Miguel Méndez and

Peace Corps The Peace Corps is an independent agency and program of the United States government that trains and deploys volunteers to provide international development assistance. It was established in March 1961 by an executive order of President John F ...

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''. Méndez took his young daughter's name Larissa and the

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

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 Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. All ...

sediment, washed into the sea by the Bahoruco River. An upstream search revealed the

in situ ''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in ...

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficia ...

s in the range and soon the ''Los Chupaderos'' mine was formed.Woodruff, R.E. and Fritsch, E., 1989. ''Blue pectolite from the Dominican Republic.'' ''Gems & Gemology'', 25(4), pp.216-225.

Geology

Larimar is a type of

or a rock composed largely of pectolite, an acid silicate hydrate of

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

and

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

. Pectolite is found in many locations, but larimar has a unique ''volcanic blue'' coloration, which is the result of copper substitution for calcium.Kloprogge, J.T., Wood, B.J. and Desk, S., 2016. ''X-ray Photoelectron Spectroscopy study of so-called “Larimar”, blue pectolite from the Dominican Republic.'' ''SDRP Journal of Earth Sciences & Environmental Studies'', 1(2). pp.58-67.

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

rocks,

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predo ...

s and

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

s, erupted within the

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

s of the south coast of the island. These rocks contained cavities or

vug A vug, vugh, or vugg ( ) is a small- to medium-sized cavity inside rock. It may be formed through a variety of processes. Most commonly, cracks and fissures opened by tectonic activity (folding and faulting) are partially filled by quartz, ...

s 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 Dyke (UK) or dike (US) may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), a subvertical sheet-like intrusion of magma or sediment * Dike (mythology), ''Dikē'', the Greek goddess of moral justice * 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.

Los Chupaderos

The most important

of blue pectolite is located at ''Los Chupaderos'' in the section of ''Los Checheses'', about southwest of the city of Barahona in the southwestern region of the Dominican Republic. It is a single mountainside now perforated with approximately 2,000 vertical shafts, surrounded by rainforest vegetation and deposits of blue-colored mine tailings.

Jewelry

Larimar jewellery is offered to the public in the Dominican Republic, and elsewhere in the Caribbean as a local speciality. Most

jewellery Jewellery ( UK) or jewelry (U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a wester ...

produced is set in

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

, but sometimes high-grade larimar is also set in gold. Quality grading is according to coloration and the typical mineral crystal configuration in the stone. Larimar also comes in green and can have red spots, brown strikes, etc., due to the presence of other minerals or oxidation. The more intense the blue colour and the contrast in the stone, the higher and rarer is the quality. The blue colour is photosensitive and fades with time if exposed to too much light and heat.

References

External links