Fibrous pectolite has long been a curiosity for gem collectors. Compact material can make wonderful cabochons, and transparent crystals are rare and usually tiny. In 1974, blue pectolite was found in the Dominican Republic. Known by the trade name Larimar, this blue gem has since become a popular jewelry stone.
a = 1.595-1.610; β = 1.605-1.615; γ = 1.632-1.645. Biaxial (+), 2V = 50-63°. Refractometer spot reading at about 1.60. See “Identifying Characteristics” below.
Optic Sign
Biaxial +
Etymology
From the Greek pektos for “congealed,” because of the mineral's sometimes translucent appearance. Larimar is a combination of Lari, short for “Larissa,” and the Spanish mar for “sea.” Miguel Méndez and Norman Rilling discovered this blue pectolite variety in the Dominican Republic in 1974. Larissa was the name of Méndez's oldest daughter.
Occurrence
In cavities in basaltic rocks, associated with zeolites; in lime-rich metamorphic rocks.
Inclusions
Hematite can create fern-like “red plume” patterns, calcite crystals.
Although the mineral pectolite occurs in locations across the globe, these fibrous aggregates are seldom cohesive enough to cut and usually too soft and fragile for jewelry wear. However, if pectolite’s fibers grow intertwined, it can become jade-like in toughness as well as appearance.
With colors ranging from white to various shades of blue, pectolite from the Dominican Republic is the loveliest in the world. Traces of copper contribute to this blue coloration. The finest stones are dark blue and translucent, but sky blue specimens with cloud-like patterns are also highly prized. Known by the trade name Larimar, this variety of compact pectolite can take a very high polish. Though locally abundant, Larimar is a rare gem material.
Some Larimar gems may resemble turquoise or dyed howlite, and other compact pectolites may resemble jade. Again, these can usually be distinguished easily.
The Dominican Republic is the principal source of gem-quality pectolite. Larimar is typically cabbed instead of faceted.
Larimar stones from the Filipinas Larimar Mine, Los Checheses, Sierra de Baoruco, Barahona Province, Dominican Republic. Photo by Géry Parent. Licensed under CC By-ND 2.0.
In Canada, the Thetford Mines and Asbestos, Quebec produce magnificent, prismatic crystals. Indeed, these are the only sources of transparent, facetable pectolite, yielding twinned crystals up to 5” long in colors ranging from white to pale blue-green.
In the United States, Alaska produces massive, jade-like stones (used as jade substitutes) as well as fine-grained, pale blue-green material. Magnet Cove, Arkansas yields pinkish manganiferous material. Lake County, California produces dense material suitable for cabochons. New Jersey has numerous sources, including the Paterson area (fine radial sprays), Bernards Township, Franklin, and Sterling Hill.
Other notable sources include the following locations:
Czech Republic; Greenland (manganiferous material); Japan; Morocco; Russia; South Africa; Sweden; Scotland, United Kingdom.
Lapidaries have cut cabochons up to a few inches from dense, massive, or fibrous material. Small, faceted gems mined in 1973 from Asbestos, Quebec range in size up about 3 carats, but only a few stones have been faceted.
Care
Although some pectolite stones, especially Larimar, are relatively tough, their hardness range (from 4.5 to 6) makes them susceptible to scratches. Popular jewelry stones, such as quartz, topaz, corundum, and diamond, will scratch them. So, store your pectolite jewelry separately from such pieces. Use protective settings for rings. Pectolite cabs make excellent stones for pendants and earrings.
Clean your gems and jewelry pieces with a soft brush, mild detergent, and warm water. Consult our gemstone jewelry cleaning guide for more recommendations.