Larimar
Encyclopedia
Pectolite
Pectolite is a white to gray mineral, NaCa2Si3O8, sodium calcium inosilicate hydroxide. 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 specific gravity of 2.7 to 2.9. The gemstone variety, larimar, is a...
found only in the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
, in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
. Its coloration varies from white, light-blue, green-blue to deep blue.
History
The Dominican Republic's Ministry of Mining records that on 23 November 1916 Father Miguel Domingo Fuertes Loren of the BarahonaBarahona
Barahona is a province of the Dominican Republic.The Barahona Coast is located on the southwestern part of the Dominican Republic approximately three hours drive from Santo Domingo the capital of the Dominican Republic....
Parish requested permission to explore and exploit the mine of a certain blue rock he had discovered. Pectolite
Pectolite
Pectolite is a white to gray mineral, NaCa2Si3O8, sodium calcium inosilicate hydroxide. 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 specific gravity of 2.7 to 2.9. The gemstone variety, larimar, is a...
s were not yet known in the Dominican Republic and the request was rejected.
In 1974, at the foot of the Bahoruco Range
Baoruco Mountain Range
Baoruco Mountain Range is situated in the Baoruco Province in the far southwestern corner of the Dominican Republic...
, the coastal province of Barahona, Miguel Méndez and Peace Corps
Peace Corps
The Peace Corps is an American volunteer program run by the United States Government, as well as a government agency of the same name. The mission of the Peace Corps includes three goals: providing technical assistance, helping people outside the United States to understand US culture, and helping...
volunteer Norman Rilling rediscover Larimar on a beach. Natives, who believed the stone came from the sea, called the gem Blue Stone. Miguel took his young daughter's name Larissa and the Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
word for sea (mar) and formed Larimar, by the colors of the water of the Caribbean Sea, where it was found. The few stones they found were alluvial sediment, washed into the sea by the Bahoruco River. An upstream search revealed the in situ
In situ
In situ is a Latin phrase which translated literally as 'In position'. It is used in many different contexts.-Aerospace:In the aerospace industry, equipment on board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may...
outcrop
Outcrop
An 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 superficial deposits are covered by a mantle of soil and vegetation and cannot be...
s in the range and soon the Los Chupaderos mine was formed.
Geology
Larimar is a variety of pectolitePectolite
Pectolite is a white to gray mineral, NaCa2Si3O8, sodium calcium inosilicate hydroxide. 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 specific gravity of 2.7 to 2.9. The gemstone variety, larimar, is a...
, or a rock composed largely of pectolite, an acid silicate hydrate of calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
and sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
. Although pectolite is found in many locations, none have the unique volcanic blue coloration of larimar. This blue color, distinct from that of other pectolites, is the result of cobalt substitution for calcium.
Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
volcanic rocks, andesite
Andesite
Andesite is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende. Magnetite,...
s and basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
s, erupted within the limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
s of the south coast of the island. These rocks contained cavities or vug
Vug
Vugs are small to medium-sized cavities inside rock that may be formed through a variety of processes. Most commonly cracks and fissures opened by tectonic activity are partially filled by quartz, calcite, and other secondary minerals. Open spaces within ancient collapse breccias are another...
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
Dike (geology)
A dike or dyke in geology is a type of sheet intrusion referring to any geologic body that cuts discordantly across* planar wall rock structures, such as bedding or foliation...
and plugs. When these rocks erode the pectolite fillings are carried downslope 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 outcropOutcrop
An 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 superficial deposits are covered by a mantle of soil and vegetation and cannot be...
of blue pectolite is located at Los Chupaderos, in the section of Los Checheses, about 10 kilometers southwest of the city of Barahona
Barahona
Barahona is a province of the Dominican Republic.The Barahona Coast is located on the southwestern part of the Dominican Republic approximately three hours drive from Santo Domingo the capital of the Dominican Republic....
, in the south-western 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 jewelry is offered to the public in the Dominican Republic, and elsewhere in the Caribbean as a local speciality. Most jewelry produced is set in silverSilver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, but sometimes high-grade larimar is also set in gold. It also has become available elsewhere. Some Far-East manufacturer have started to use it in their production and buy large quantities of raw stones as long as this is still permitted.http://www.hoy.com.do/economia/2008/1/12/109448/Invertiran-US400-millones-enequipos-exportacion-agregados
Quality grading is according to coloration and the typical mineral crystal configuration in the stone. Larimar also comes in green and even with red spots, brown strikes etc. due to other matters and / or oxidation. But the more intense the blue, and the contrasts in the stone, the higher and rarer is the quality. The blue color is photosensitive and fades with time if exposed to too much light and heat.
Specifications
- Name: Larimar
- Family: Pectolite
- Variety of: Pectolite, NaCa2Si3O8(OH)
- Composition: Hydrated sodium calcium silicate with manganese
- Origin: BarahonaBarahonaBarahona is a province of the Dominican Republic.The Barahona Coast is located on the southwestern part of the Dominican Republic approximately three hours drive from Santo Domingo the capital of the Dominican Republic....
, Dominican RepublicDominican RepublicThe Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
, La Hispaniola, CaribbeanCaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north... - Hardness: 4.5-5
- Color: varies between white, light blue, sky blue, green-blue, and deep blue
- Uses: ornamental stone and semi-precious stone
- Cleavage: perfect in two directions, but not seen in this compact form
- Crystal System: triclinic